Work Text:
What if the Aqua from Konosuba USED to be the Aqua from Kingdom Hearts? This only starts showing itself after the job where Aqua was in that cage purifying a lake. She doesn't want to stay in the cage, Aqua just... wordlessly exits after Kazuma tells her to get out. She doesn't say ANYTHING for the rest of the day, actually. But the next day, Aqua... doesn't act like her Konosuba self anymore. She's... nice? Thoughtful? Smart? Hell, gently teasing even? Who are you, and what have you done with that useless goddess? The idea is that the KH Aqua personality is who the Konosuba Aqua was always underneath. She acknowledges and apologizes for her earlier attitude, explaining her trauma and just WHY she was such a brat and drunken lush. It was all coping, but coping that got so out of hand that she forgot her real self until that time in the cage. (Her time as Kingdom Hearts Aqua would have been thousands of years ago, so she's not looking to get back to Terra and Ventus and the like, especially since this is set LONG after even Kingdom Hearts 3.) Aqua was the Konosuba Aqua long before arriving in Axel with Kazuma, hence her attitude during episode 1 of Konosuba!
In an AU story of Konosuba where Komosuba Aqua used to be Kingdom Hearts Aqua but became Konosuba Aqua out of bad coping mechanisms tp deal with... literal eternal life so much that she almost forgets her original self... what if, soon as she's in Qxel when Lazuma, like in canon, picks her as his boon, brings back Anti-Aqua from Kingdom Hearts 3? I don't mean immediately, but eventually, like maybe she starts out as a hallucination for Aqua after the cage incident in episode 5 of season 1. Oh no, Anti-Aqua is fully a villain. She is resentful as FUCK about Aqua hiding her true self behind this joke of a Persona and wants to tear down everything that makes this Aqua the Komosuba Aqua. This version does not let Aqua's return to her Kingdom Hearts personality be gentle. Anti-Aqua is basically dragging her kicking and screaming back into her true self again or risk the death and pain of everyone she loves or has ever loved. Anti-Aqua is doing this full on out of resentment, not caring to try a gentler method because that wouldn't satisfy the literal centuries of anger Anti-Aqua has for Konosuba Aqua's existance. So even when the Kingdom Hearts Aqua returns, Anti-Aqua doesn't just disappear, she still wants to rage against her original, still wants to see her suffer for what she's done.