Here I will list the points in the game where the story has been altered. I am also open to suggestions.
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-Chapter 1
Chapter 1 revolves quite a bit around Tietra, as it originally did with Algus, who does not join you for long in this game.
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Igros Garden
The first change that you will notice? Delita will ask Tietra to come with the group to Dorter. Algus will stay behind at Igros asking to have a discussion with Zalbag.
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Sweegy Woods
Obviously its different, Tietra s with you. Besides that, Delita finds a "beautiful" stone on the ground and gives it to his sister for good luck.
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Slums in Dorter
Tietra is with you instead of Algus.
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Dorter Interrogation
Tietra performs the interrogation, her actions here reveal a not so subtle change in her attitude.
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Cellar of Sand Mouse
Tietra's attitude gets worse as she takes similar actions towards Wiegraf that Algus would have had he been there.
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Thieves Fort
Tietra takes the actions in place of Algus, there are a few dialog changes.
At this point Delita should begin questioning the stability of his sibling.
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Igros
Algus gets abducted from Igros since he is in the castle instead of Tietra.
He is mistaken for the youngest Beoulve son. Tietra tells Delita that its not worth saving a common fencer and in the end she is expelled from the Beoulve residence.
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Mandalia plains scene
A scene at mandalia plains shows the last sight you get of Tietra in Chapter 1. Here you see that Tietra is puzzled by her own actions and claims, to her two newly hired units, that she feels a voice inside her head telling her what to do.
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Lenalia Plateau
Two generic units get some attention here, Jade and Fabian. After defeating Miluda here, she tells Ramza "this isn't over" and orders Jade and Fabian to run. The three of them escape and are not seen again for quite some time.
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Windmill Shed
Obviously Algus is the hostage here instead of Tietra. Slight dialog changes. During the battle, if all the lines are allowed to play Ramza insists to Wiegraf that Miluda is still alive. Wiegraf does not believe him because she is nowhere to be found. The rest of the event pans out normally.
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Ft Zeakden
Poor abucted Algus, I wonder how he would have felt if he had the memory of what he had done in the original game. Zalbag does not make an appearance here clearing him from being an asshole like in the original when he gave the order to shoot. Currently a common fencer fires the arrow. This could be changed later.