Walter's going to be looking for the people he cares about and basically trying to safeguard them. Ash is gonna be his usual self and fight tooth and nail to drive the UB's back

I think Walter's Zweilous is gonna evolve in this event, cos he's certainl at the right level too

Chaos will be safeguarding the vents and the rest of his Pokemon will largely be with Walter, although Darkness will be taking wing to find and check up on Walter's CR

In Ash's team, DANNY'S GONNA MEGA EVOLVE AND PUNT EVERYTHING

But Holokai's gonna try and telepathically connect/speak with them, and it's gonna really rattle him and throw off his flow D8 like an oil spill in the ocean of the world's vibes