Here’s an Idea.
RWBY story until it's not. Oc Mc is from the RWBY Universe but is sent visions in his dreams of an invasion from another universe.
Given mental blueprints of weapons to combat the invaders.
Arms important people with the means to fight the invaders.
Full-on invasion eventually happens and Mc fights a recognizable villain.
I be ’n like crazy tbh. I’ve obviously been in a massive slump as of late story-wise.
Probably just gonna keep throwing ideas at the wall and see what sticks.