Final Fantasy Hacktics

High tier job (Replaces calculator) can heal/buff/create undead and use Dark elemental spells

Job Purpose: Melee/Magic/Support/Tank
Job Description: Religious unit who supports his allies in the midst of battle.
Gender Availability: Both
Skillset Name: Faith
Skillset Description: Calls upon the power of the gods to administer first aid and magical enhancements to allies.
Ability Types: Weak-Moderate Healing/Buff Spells
Additional Info: Wears armor despite being a casting-based unit. High MP/Moderate-Low MA (Shouldn't be needed for much other than Healing spells, and can always deck the unit out for MA if desired).

Job Purpose:           Support
Job Description:       A nomad who is often seen traveling with groups of monsters, seem to be accepted by monsters as their alpha
Gender Availability:   Both
Skillset Name:          Monster Lore
Skillset Description:  Uses a unfamiliar form of speech and hand signals to boost the ability of surrounding monsters
Ability Types:          This character would ideally use mediator type moves to buff/heal monsters
Additional Info:        Innate: Monster Skill
                            Innate: Monster Talk

Job Purpose: Ranged/Magic/Harassment
Job Description: An archer who enchants her arrows with magic to disable enemies.
Gender Availability: Both
Skillset Name: Arcanum
Skillset Description: Magically enchanted strikes used to harass enemies.
Ability Types: Weapon ranged attacks that inflict status effects.

Job Purpose: Skirmisher (Melee/Ranged/Magic/Damage)
Job Description: Warrior dedicated to both spell and sword, slays opponents quickly and without regard for personal safety
Gender Availability: Both
Skillset Name: Blade Magic(ks)
Skillset Description: Channel magic(k) through blades to devastate foes quickly.
Ability Types: High damage single target, Area 1, and Linear attack spells of varying ranges and self buffs.
Additional Info: This unit wears clothes and robes and uses daggers, swords, and knight swords. She has self buffs that bestow things like shell, reflect, and haste, but nothing that increases physical durability like defend and protect. It has high Speed and MA, and above average MP, but low PA and HP. She should skirmish between ranged combat and melee combat by switching between single target ranged spells that deal moderate damage and close ranged spells that have Area or do lots of damage.

Her big attacks encourage her to get into melee to slay vulnerable targets or to eliminate big threats but her low hit points encourage tactical usage. She should have several different elemental types to choose from.

Job Purpose: Melee/Damage/Support/Tank
Job Description: Sworn to fulfill their oath, no matter the cost.
Gender Availability: Both
Skillset Name: Arts of War
Skillset Description: Knight Job command. Protect allies or destroy enemies at the cost of one's own health.
Ability Types: Aside from status breaks the Knight should also have abilities that make use of the Knight's large supply of HP, such as Wish or Darkside (like wish but with damage instead of healing) or things like White Wind and Minus Strike if possible.
Additional Info: This could be a special class for Lavian and Alicia, or it could be split between them so one has the offensive abilities and the other has the defensive abilities.

Job Purpose: Support to the max!
Job Description: One who does not fight in battle, but rather chooses to wield power to aid allies.
Gender Availability: Both
Skillset Name: Peacemaking or Pacifism
Skillset Description: Power used by those who do not fight, it cannot be used for harming others. (though it can help your allies harm others XD)
Ability Types: Ability's much like the priests, wall, protect, shell, a variation of cure which does not harm the undead ( giving them good PA can allow the chackra formula to be used here) and other special healing abilities that are not holy based, the pacifist isn't always a believer in god, they just don't want to hurt people.
Additional Info: In the job tab of the FFTP un-check all boxes that have anything to do with weapons (INCLUDING the box next to the blank, therefore making the attack command for this job useless), just give them really powerful supporting ability.

Transforms into monsters for special attacks.  It's possible to make skills that cause a unit to disapear before the spell effect is played out.  For example:

Unit "Shifts" into salamander (or midgar swarm) effect.  or other believable summon effects.  I have never looked into editing the effect spells- But I imagine it might be possible to find one that would be suitable to insert a standard monster frame into and look okay...

Imagine the dragon transformations from Breath of Fire 2.  .....keep dreaming Hacktics!!!

Equip: Swords, Shields, Robes, Heavy Armor

Skillset Name: Judgement

-Recommended: Fire (Add: Oil on all units, persevere)
-Forbidden: Speaking (Add: Silence on all units, persevere)
-Forbidden: Moving (Add: Immobilize on all units, persevere)
-Forbidden: Healing (Add: Undead on all units, persevere)
-Forbidden: HP < 100% (Heals all units, persevere)
-Recommended: HP < 100% (Damages all units, persevere)
-Recommended: Magic (Protect/Wall on all units, persevere)
-Recommended: Melee Attacks (Shell/Reflect on all units, persevere)
-Antilaw (Cancel: Performing[Persevering])
-Red Card (Add: Immobilize/Disable)

EQ: Bag, Knife, Instrument, Clothes, Hat, Accesories
INNATE: Secret Hunt

Feathery Soul      Poach from Chocobo/Juravis, Draw Out Radius +Reflect AND Regen
Demonic Soul       Poach from Skeleton/Ghost, Draw Out Radius +Undead
Draconic Soul      Poach from Dragon/Tiamat, Draw Out Radius, MA * 10 Damage
Horned Soul        Poach from Minotaur/Behemoth, Draw Out Radius, Enemies Only, Fire Elemental, MA * 8 Damage
Plain Soul         Poach from Goblin/Cuar, Draw Out Radius, Enemies Only, Nature Elmental, MA * 8 Damage
Sapient Soul       Poach from Squidlarken/Dryad, Draw Out Radius (include Self), MA * 10 Healing
Abomination Soul   Poach from Murbol/Floatiball, Draw out Radius, +Blind
Bomb Soul          Poach from Bombs [rare], Draw Out Radius, Kill Self, Deal maxHP - curHP DMG to units in range
Pig Soul           Poach from Uribo, Draw Out Radius, MA * 5 MP Healing
Lucavi Soul        Drop from Lucavi, Draw Out Radius, Enemies Only, +Death Sentence

Auto Potion        Use a potion and heal for Max{LVL, 30} HP, IF NONE, FAIL
Secret Hunt

Job Purpose: Versatile Combatant but lacking in selection: unarmed, bows, crossbows, & knives.  May Dual-Wield with knives or fists.  Known for solid damage output against specific single targets but struggles with crowd control and lacks staying power.  Reasonably agile.  Melee & Ranged, Damage and light Harassment, but no Support or Tank function.  Innate Poach, Dual-Wield, and Reequip.

Job Description: A skillful wanderer of the wilds who tracks down and slays any creature in any environment.
Gender Availability: Both
Skillset Name: Stalk
Skillset Description: Ranger Class Command.  Strikes down prey with murderous precision and mundane savvy.
Ability Types: "As Weapon" instant Attack Modifications similar to Art of War/Battle Skill and Snipe/Aimed Shot.  This will require a couple things.  First, you have to be able to flag certain characters and monsters as specific creatures, or being magical, and that this may extend to Classes as well.  Second, the skills will only target these characters.  There will also be a few that work on anybody, just to be nice about it.

Envenom - Adds Poison to Target.
Fiery Hit - Modifies hit into a Fire Affinity attack (often to make fire arrows or to ignite blades); supplants a weapon's other effects.
Goblin Killer - Attempts to score a lethal blow against a Goblin-Type enemy, killing them on success.
Magislayer - Attempts to score a crippling blow against any magic user, which includes certain monsters and many Classes such as the Black Mage or Summoner.  Character must be flagged as "Magic" as part of their description like how monsters may be flagged as Draconic or Undead.  This will add damage, but does not dish out instant kills.
Pin Down - Surgically pin an opponent to a position, adding CT 0.  Always hits.  Should be reapplied regularly to hold sucker in position so others can help kill it.  Also cancels Preparation conditions (Defend, Perform, Charge/Cast).
Dragontear - Surgically damage dragons.  May also affect Dragoon/Lancers (so if Reis has her Dragonkin abilities, it'll affect them), severing the sanctity of the Order of Dragon's covenant with the proud beasts.
Exorcism - While Seal Evil and Raise 2/Arise are good, this delivers a powerful chastisement upon an Undead creature that adds one of a list of debilitating status effects that would conceivably affect their ability to fight back (so no Poison or Faith, since these don't appear to affect them so much).
Kill Horror - Deal better damage against Lovecraftian Horrors such as Illithids (the fucking Pisco Demons), Marlboroughs and even late-game freaks like Archaic, Ultimate, and Reaver-type opponents.  This could also overlap with Eye Beasts, assuming they are also flagged as magical.  But this is for those times when you want the creature to die faster.

Additional Info: The Ranger is an offshoot or hybrid of the Ninja and Archer respectively.  Instead of Throw or Charge/Aim, a new set of abilities comes into place.  Rangers, in Dungeons & Dragons, habitually possess either Dual-Wield or Archery combat mastery, and in the MMO, they get both.  They also acquire camouflage so adding Sunken State to the list of Reaction Abilities seems in good order.  However, you can chuck a few things here and there.  I mean, here's what a Ranger looks like, overall:

Equip Dagger, Bow, Crossbow, Hat, Outfit, all Accessories; cannot equip shields like the Archer did while using Crossbows
Innate Dual-Wield (optional), Poach
Reaction Abilities: Sunken State, Adrenaline, Archer's Bane
Support Abilities: Equip Crossbow, Concentrate, Poach, Train (cannot teach Dual-Wield if Dual-Wield is featured)
Movement Abilities: Probably some low-to-mid grade number like Jump + 2 or Move + 2, or Swim, or Terrain-Oriented ones like Any Ground & Any Weather (modified or hybridized with other effects so as to be more attractive to players).

In all, this one's likely to get thrown out without heavy modification, but feel free to switch things around if you like.  If having to flag creatures as a certain type seems too daunting, it would be best to use something else in its place, only no Aim/Charge.  That just gets dull.

EQ: Sword, Axe, Instrument, Shield, Clothes, Robe, Hat, Accessories
INNATE: Move-in Water, Move-on Lava

Pitfall       Earth Elemental, +19% Don't Move
Water Ball    Water Elemental, +19% Frog
Hell Ivy      Nature Elemental, +19% Poison AND Blind
Carve Model   Earth Elemental, does more damage than the others
Local Quake   Earth Elemental, +19% Slow
Kamaitachi    Wind Elemental, +50% Cancel: Protect, Shell, Reflect
Demon Fire    Fire Elemental, +19% Oil
Quicksand     Water Elemental, +19% Stop
Sand Storm    Earth Elemental, +19% Sleep
Blizzard      Water Elemental, +19% Addle
Gusty Wind    Wind Elemental, +19% Don't Act
Lava Ball     Fire Elemental, +19% Dead

Counter Flood
Move-in Water
Move-on Lava

Job Purpose: Damage/Tank
Job Description: A Knight who was taught some of the abilities of the mythical "Zodiac Braves".
Gender Availability: Both
Skillset Name: Zodiac/Zodiark(So the class name and Skillset are not THAT alike)
Skillset Description: Enables the use of the Zodiac Braves' Abilities.
Ability Types: I imagine it would be something like Beowulf's abilities, but with elemental for the damages. Ex: Aquarius would be water Elemental, while Pisces non-elemental but based on MA/Faith.
Additional Info: Since they made up the Serpentarius Sign, there could be something of an Ultimate skill, only learnable after learning the others, or after a certain point in the game. The Zodiac Knight should also have the ability to buff his own defense, or mark himself as a target, so that the other members may heal/prepare themselves.

Job purpose: Support/Harassment
Job description: Heralds of astrology who warp the dimensions of time and space. Uses Astrology to manipulate fate and sway the course of battle.
Genders: Both
Skillset Name: Astrology
Skillset Description: Harbinger job command. This augur toys with the laws of the universe.
Ability Types: (General 'Time Magic' spells, but re-purposed and re-envisioned, with more emphasis on "space" or placement.)
Here is a small sample of possible abilities: (Speed/MP values withheld for the sake of avoiding complexity.)

Astral Flux - ~100 JP - Hastens the passage of time of those in line with the stars. (Add: Haste. Effects all nearby units in range of 1.)
Phase Grip - ~250 JP - Halts the passage of time with the pulse of a star, severing the target from time's flow. (Add: Stop. Effects only one unit within a range of 3.
Dimensional Rift - ~450 JP - Tears holes in the fabric of time. Reduces the HP of units in a large area by 33%. (Range of 2, AoE Effect range of 2 (always effects caster), vertical range of 3)
Time Reversal - ~550 JP - Rewind the stars, balancing time and even reversing death itself. (Cancels all: Dead, Haste, Slow. Centered on caster, radius of 1.)
Celestial Stasis - ~650 JP - Halt the course of enemies' guardian stars, rendering them, and yourself, completely unable to act. (Inflicts any: Stop, Don't Act, Don't Move. Centered on caster, radius of 3 or 4, infinite vertical tolerance.)
Parallel Balance - Hidden ability/Auto-Learned/0 JP - Warps time and space to inflict damage commensurate with the damage the user has endured. (Requires Critical status on caster. Range of 5. Effect of 1.)
Temporal Boon - Hidden ability/Auto-Learned/0 JP - Voids your existence while gifting a second chance to another. (Cancel: Stop, Sleep, Petrify; Adds: Quick, Haste. Requires Critical or Doom status on caster & kills caster after casting. Range of ~5 (or infinite range?))
SUPPORT
Alacrity (Short Charge) - Halves CT of Spells and Abilities

Additional Info: (Inspired by the "Nightshade" class of FFTA.) As such, and with a job name such as 'Harbinger', I would style them as sword/katana-bearing dimensional warriors that can equip robes for added flavor.)

As for its abilities, I was trying to go for inter-skill conflict. (Abilities should conflict with one another.) However... use 'Dimensional Rift' three times, and then use 'Parallel Balance' to great effect?

On the grand scale, I figure each job's skillset will have a couple of auto-learned/invisible abilities that are only useable when Critical/Doomed respectively. (Doom wouldn't be inflictable by the player.)

EQ: Knife, Sword, Bag, Clothes, Hat, Accessories
INNATE: Throw Item

Knife
Shuriken 
Ball
Axe
Spear
Item

Throw Item

EQ: Spear, Axe, Shield, Armor, Robe, Helm, Accessories
INNATE: JUMP 1v1

Jump Level +1  (+1 Range/Tolerance)
Jump Level +1  (+1 Range/Tolerance)
Jump Level +1  (+1 Range/Tolerance)
Jump Level +1  (+1 Range/Tolerance)
Jump Level +1  (+1 Range/Tolerance)

Equip Spear
Equip Armor

EQ: Stick, Rod, Staff, Robes, Clothes, Hats, Accessories

CT3 (If you choose CT, your second parameter is automatically 3)
LevelPrime (If you choose Level, your second parameter is automatically Prime)
Height5 (If you choose Height, your second parameter is automatically 5)
EXP4 (If you choose EXP, your second parameter is automatically 4)

Calculable Spells:
The entire vanilla skillset except Holy, Flare, Raise2, Foxbird, Petrify, Stop, Frog, Sleep, Don't Act, Demi2

EQ: Sword, Knife, Shield, Robes, Clothes, Hats, Accessories

Level
EXP
Height
Prime
5
4

Calculable Spells:
Fire
Ice
Bolt
Cure
Regen
Reraise
Dispel Magic
Esuna
Pray Faith  (needs a formula not dependent on faith)
Doubt Faith (needs a formula not dependent on faith)
Zombie
Poison
Blind
Don't Move
Reflect
Float
Demi / Life Drain (Either is fine.)

Purpose: Melee/Status/Harassment

Description: Utilizes stealth and confusion in order to land the perfect killing blow

Gender: Both Male and Female

Skillset Name: Lethal Arts

Skillset Description: Variety of brutal methods to overcome enemies

Equips: Knives, Bows, Ninja Swords, Clothes, Accessories

Innate: Dual Wield

Skills: Meteor Assault (Adds Blind), Reaper (Adds Death), Cloak (Adds Transparent), Grimtooth (similar to Earth Slash Animation but using weapon), Sonic Blow (knock back damage), Venom Splasher (AoE Poison), Allure (Adds Charm), Soul Destroyer (AoE Damage)

Purpose: Melee and debilitation

Description: Warriors who wield spears to debilitate and overwhelm foes

Gender: Both

Skillset Name: Spearplay

Skillset Discription: Several moves that hinder and damage opponents

Equips: Spears, Clothes, Accessories

Innate: Two-Hands

Skills:
Pin (inflicts half-damage, adds Don't Move)
Forceful Strike (deals lower damage, but is a guaranteed knockback if it hits)
Longinus (An aimed attack that pierces all enemies in the weapon's attack range, requires a spear)
Aimed Blow (strikes at the opponents joints, inflicting Don't Act)
Clobber (a forceful blow with the spear's shaft to the target's head, adding Confuse and lowering MA)
Full Thrust (deals massive damage(maybe 1.5?), but has low accuracy and weakens the user, taking away 1 or 2 PA each use)

Might edit as I think of more abilities. Hmm.....

Job Purpose: Magic/Harassment
Job Description: Arcane practitioner that focuses in torturing his enemies.
Gender Availability: Both
Skillset Name: Curse
Skillset Description: The Warlock curses his enemies to render them incapable of fighting effectively.
Ability Types: De-buff spells/DoT
Additional Info: Can wear clothing or robes. Low MP/High MA (Used for dealing damage with books. If books remain physical, then the Warlock's PA will increase, while his MA will decrease).

Job Purpose: Melee/Damage/Harassment
Job Description: Warrior mages who enhance the power of their weapons with magic.
Gender Availability: Both
Skillset Name: Spellblade
Skillset Description: Adds a magical effect to the Mystic Knight's physical attack.
Ability Types: Mostly weapon-range elemental attacks that can also inflict statuses, similar to the Parivir from FFTA2.
Additional Info: Reaction abilities may include SOS Protect or SOS Shell if considered viable and balanced.

Job Purpose: AoE Magic Damage

Job Description: Mages who devastate their opponents with powerful and forbidden magic

Gender Availability: Both

Skillset Name: Arcana

Skillset Description: Magic powerful and devastating that does not discriminate from friend or foe.

Equipment: Rods, Staves, Books, Robes, Hats, Accessories

Abilities:

Blackout- Dark Elemental damage (AoE of 2, uses Darkness 2's effect)

Whiteout- Holy Elemental damage (AoE of 2, uses a whitened version of Darkness 2's effect)

Rejuvinating Rain- Water Elemental healing (AoE of 3)

Fatal Eclipse- Non Elemental damage (AoE of 3, Range of 0, uses Grand Cross's effect and hits the user)

Crimson Flare- Massive Fire damage (AoE of 2, uses Flare 2's effect)

Animalcule- No damage, inflicts status (Add Darkness, Poison, Silence, Don't Act: AoE of 1)

All abilities have a range of 3

I know this might seem a bit powerful, but all of the skills hit allies as well as enemies. JP costs might be expensive as well. Based off of the Arcana magic from The Last Remnant (though nowhere near as powerful)

Hybrid class capable of swordplay and various monster abilities
EQ: Swords, Rods, Staves, Clothes, Robes, Hats, Accessories
Special Abilities: Can learn monster skills from crystals
I'm thinking we either make monster skill and talk innate on all units or make both innate on blue mage.

Abilities (mostly support, but you have some nice damage skills too):
Choco Esuna
Circle
Beaking
Sleep Touch (You can only learn this through crystals.)
Blood Suck (This is the vampire cat version that only has a 25% chance of adding blood suck.)
Hurricane
Mimic Titan
Odd Soundwave
Look of the Devil
Nose Breath (Best learned through crystals.)
Protect Spirit
Calm Spirit
Sudden Cry
Triple Attack

Things not considered for balance reasons:
Blaster
Blow Up
Bad Breath
Triple Breath
Almagest
Oink
Gather Power

NOTE: The inclusion of Blue Mage necessitates monsters having stats similar to humans or a change of monster damage/status formulas

Job Purpose: Support/Anti-Magic/Annoying
Job Description: Heretic hunting magis' bane
Gender Availability: Both
Skillset Name: Bane Magic
Skillset Description: Archaic form of magic used to obliterate and dismantle magic.
Ability Types: Buff/Negative/Status Spells
*Mana Strip - MP Damage
*Void Bliss - Ranged Dispel (enemy)
*Magic Mockery - Cancel casting, Add berserk
*Mirror Stance - Add Reflect (self)
*Anti-Faith - Reduce faith (self/enemy)
*Charm Crush - Breaks accessory
*Silent Lake - Add silence (all units)

Job Purpose: Support/Caster

Job Description: Protector of the wilds, avenger for nature.

Gender Availability: Both

Skillset Name: Nature magic

Skillset Description: Magic that is derived from nature herself. The Druid uses the gift she blessed upon him to protect those who cannot protect themselves, and to harm those who would destroy what is most precious to her, the wonders of nature.

Ability Types:
Geomancy (only the ones on natural terrains like Hell Ivy, Water Ball, Quicksand etc)
Basic white magic (cure 1, protect 1, shell 1, Raise 1)
Basic Black Magic (Bolt 1, Bolt 2, Poison)
Throw stone

Lower stats and 3 move, good speed.

-Stopshot: Weapon damage with 25% add stop

-Potionshot: Recovers HP in weapon range

-Ethershot. Reovers MP in weapon range

-Iceshot: Ice Weapon Damage in weapon range

-Rend Helm: Destroys enemy Helmet in weapon range

-Fire Blast/Mortar: 150% Fire Weapon damage in weapon range, but recoil to caster Damage/3

-Silenceshot: Add silence

-Firecracker: 150% Weapon damage, cost 22MP  (Maybe up the MP or change by another ability, because my game has another MP system)

Reaction:

Interference: Like Arrow guard, but with guns. The hack actually exist.

Support

Equip Guns or concentrate?

Job Purpose: Melee/Ranged/Damage/Harassment
Job Description: Adventurer who battles the forces of darkness using a collection of legendary weapons.
Ability Types: Charge, but with a lower CT than the core archer has. This class should also have Change Equipment innate.
Additional Info: There should be a special weapon type only this class can use which would actually be a collection of various different types of weapons, each specialized for a different purpose. All of the weapons in its collection will have different attributes (auto-buffs and debuffs, resistances and weaknesses, and various other properties) that make them more useful in some situations than others, encouraging the player to make use of the Change Equipment skill.

Personally, I really like the idea of making Simon the protagonist of this game, or at least a major player. The main plot could surround the church's initial contact with the Lucavi. Either Vormav's predecessor becomes possessed and convinces his buddies that it would be a good idea to find more holy stones, or he's just interested because the Zodiac Stones are valuable religious/historical artifacts. Either way, Simon (or whoever the protagonist is) aids in the search for the latter reason, and ends up inadvertently causing some incredibly terrible things to happen. The Lucavi that awaken during this game may end up being defeated, but the Leo Stone and many others are already in the possession of the church, and it's only a matter of time before Hashmal gets things going again.

The major villains of this story would probably be Shemhazai and Mateus if it's possible to get sprites for them. Otherwise, the Lucavi that appeared in FFT could be active. Elidibus should probably be in the story somewhere. Cid should also be in the story, since he seemed to know a bit about what the church was up to in FFT, and since the Libra Stone was an Orlandeau family heirloom (though I don't think the church knew that he had it.)

As for when this would take place, my preference is to make the story fairly late in the war to avoid the implication that the Leo Stone did absolutely nothing for over a decade. Around the fortieth year sounds good to me, with the relatively mysterious death of King Denamda IV possibly being worked into the plot. It should be noted that Balbaneth's older sons were already active before Denamda IV died, as Zalbaag's profile mentions praise Zalbaag received from Denamda IV for his victories during the war.

I was thinking the main character could be an average man who was conscripted into the Ivalician Army from Zelamonia during Year 31 of the war, ostensibly to defend his homeland.  Instead, following the Romanda invasion, he gets sent off to defend Ivalice and following the chaos of the Ivalician invasion, is forced to commit atrocities against Ivalice's people to "keep order".  Horrified by his actions (and by the fact Ivalice is truly no better than Ordallia), he is finally granted leave after he learns his wife died of plague, leaving him with a daughter to take care of.  Only a few years pass before Ordallia invades again, forcing him into the local militia, where he meets his end.

An Ordallian spy deep inside enemy territory.  All of the hirelings are Ivalician, however, so he's acting incognito.  When he happens upon Gafgarion in Fovoham and beholds his anarchic brutality on the front-lines, it isn't just to weaken the Ivalice campaign, it is to stop a fiend from destroying both kingdoms to win the war.  The same could be said of fighting against Gustav, who was a routine offender during the war.  Before he or she can be congratulated, the spy returns to Ordalia before suspicions arise and they reinstate the cutthroat on a technicality.

A soldier from either administration dredged into a peasant revolt.  While his team attempts to put down the revolt, both sides resort to vile associations with monsters and use unthinkable tactics.  Petitions to the Queen and the regional governors are fruitless.  However, the officer receives help from an unlikely source: the Death Corps (Knights of Death/Dead Men/Corpse Brigade), with the reigning aide-de-camp Milleuda providing both a tender ear and a trusty sword-arm when things start to fall apart.

Investigate the disappearance of Elidibus, the wizard who retook Riovanes Castle and vanished into thin air.  This can take the protagonist all over the world.  The objective is to eventually happen upon the Deep Dungeon, advance to the lowest point and engage Elidibus himself.  However, it doesn't end there.  If you choose to fight him, he will kick your butt or merely retreat.  If you pause to consider his position, you will become his little accomplice, setting out to claim Zodiac Brave Stones.  The Libra Stone is in Orlandeau's hands, while Taurus is found inside Goug's mines.  However, your character gets second thoughts each time and comes up with nothing to show.  Elidibus ends up slaying you, and the legend of the Deep Dungeon is born from your corpse: a legendary mercenary that was done in there.

Personally, I really like the idea of making Simon the protagonist of this game, or at least a major player. The main plot could surround the church's initial contact with the Lucavi. Either Vormav's predecessor becomes possessed and convinces his buddies that it would be a good idea to find more holy stones, or he's just interested because the Zodiac Stones are valuable religious/historical artifacts. Either way, Simon (or whoever the protagonist is) aids in the search for the latter reason, and ends up inadvertently causing some incredibly terrible things to happen. The Lucavi that awaken during this game may end up being defeated, but the Leo Stone and many others are already in the possession of the church, and it's only a matter of time before Hashmal gets things going again.

The major villains of this story would probably be Shemhazai and Mateus if it's possible to get sprites for them. Otherwise, the Lucavi that appeared in FFT could be active. Elidibus should probably be in the story somewhere. Cid should also be in the story, since he seemed to know a bit about what the church was up to in FFT, and since the Libra Stone was an Orlandeau family heirloom (though I don't think the church knew that he had it.)

As for when this would take place, my preference is to make the story fairly late in the war to avoid the implication that the Leo Stone did absolutely nothing for over a decade. Around the fortieth year sounds good to me, with the relatively mysterious death of King Denamda IV possibly being worked into the plot. It should be noted that Balbaneth's older sons were already active before Denamda IV died, as Zalbaag's profile mentions praise Zalbaag received from Denamda IV for his victories during the war.

I was thinking the main character could be an average man who was conscripted into the Ivalician Army from Zelamonia during Year 31 of the war, ostensibly to defend his homeland.  Instead, following the Romanda invasion, he gets sent off to defend Ivalice and following the chaos of the Ivalician invasion, is forced to commit atrocities against Ivalice's people to "keep order".  Horrified by his actions (and by the fact Ivalice is truly no better than Ordallia), he is finally granted leave after he learns his wife died of plague, leaving him with a daughter to take care of.  Only a few years pass before Ordallia invades again, forcing him into the local militia, where he meets his end.

The player is an Ordallian spy sent to find a way to disorient Ivalician resistance throughout Zeltennia in the closing days of the war.  He creates false miracles and wonders to trick the desperate Ivalician command into thinking that Elibdis has truly returned.  As the situation grows more desperate for Ivalice (and the spy gathers more people to vouch for his reliability), the events continue until the Ivalician command have no choice but to take notice.
Ivalice then sends a reasonably balanced search party of expendables to investigate Elibdis' location, led by the spy.  Included among them are many conscripts alongside the veterans of the counterrevolutionary purge mentioned in "Desperate Solider".  Obviously, Ivalice would rather them all die than have them give popular accounts of their deeds.  The spy uses this distrust to turn his band of misfits against Ivalice, causing them to further disrupt Ivalician communication and organization while feeding the news of Ivalice's massacres against their own civilians (as mentioned in "Desperate Soldier") to Ordallia as propaganda and as means to coerce Ivalice into accepting their surrender.  (In other words, by the time the spy engages in his wanton romp, he already has knowledge that the secret treaty negotiations are occurring so his mission is now to find ways to strengthen Ordallia's negotiating hand while further demoralizing Ivalice.)  When Ivalician command finally realizes their mistake and tries to chase him down, he then flees across Ivalice and chances upon Deep Dungeon, where he is transformed and his men meet their final doom.