Phantyx

Demons vanished from the world without warning, after generations of uneasy coexistence and outright war with humans, and nobody's explained why. That gap is where the story starts, with the disappearance left open rather than resolved up front.

The setup pushes a male protagonist into the aftermath, tracking down what's left of the demon side of things, which mostly means monster girls who didn't get the memo about leaving. Expect a fantasy world still carrying the scars of that old conflict.

You move through a sandbox structure, deciding where to go and who to chase down, with 3D-rendered scenes and some animation carrying the actual encounters. The sandbox layer can be switched off in settings if you'd rather skip the busywork and go straight to the point. Multiple endings mean the choices you make along the way actually land somewhere.