kinda wanna write kinda wanna take a nap

She's abrasive and difficult with the player and Zerith because she initially perceives them as threats to Krin'ze's safety, because associating with 'heretics' would make her a target for the Torval Curiata, who are an ever present threat since pressing the Cantors into service. Add in the Rajaska threat, which coincides with Zerith's return, and her trauma around necromancy, it makes sense that she starts the story as a minor antagonist meant to hinder and aggravate. She's getting in your way because you could get Krin'ze hurt or worse, and Krin'ze is her sahida, someone she loves and feels responsible for. Just like she did with Eifa, who's story did not end well.

Because it turns out that Viti had a sister who turned to necromancy and was at risk of becoming a dro-m'athra, and so Viti killed her because she would sooner kill and bind her sister's soul to keep it from Namiira than see her erased entirely. But the wounds never really healed and Eifa remained trapped in that dark cellar, and studying the Hidden Moon helped Viti to realise that Zerith could help Eifa in a way that she couldn't. So she reaches out, makes an effort to make amends, and becomes an ally against the Rajaska and the Inquisitors.

It's really typical for aromantic characters to be portrayed as deeply logical and rational with little attachment to other people, depicting them as being almost estranged from emotion. There's this expectation that just because we don't love romantically, we don't love at all and that means we must be cold and passionless. But Viti flies completely in the face of that - she loves to the point of being irrational. She loves so much that she jumps to conclusions and follows her heart rather than her head, and she has to take time to reflect in private to overcome those assumptions built off of trauma responses and past experiences in order to let a logical reasoning prevail.