This is really good! Just one small suggestion. Though you started with the US names, in between you added the Japanese names of the Chosen children (ah you used this term as well instead of digi destined) as well. It would be better if you stick to one of them (either the Japanese names and terms or English names and terms) Otherwise, in terms of plot and character development, it's really good.

I like plots similar to this where Kari becomes a dark version of herself after a tragedy. She has the potential to go on a huge rampage and cause some serious damage to anything in her path. This is a good alternative take on what could have happened after the events involving Tai in Digimon Tri. Good work. It feels like there’s more to come, right?

Please not the end... There's so much potential in this.

Loved it