Save me

(so Hello! I'm new to this Fandom. and i liked the ship named Paperhat! I'm gonna create one.)
Heroic au is included

Dr Flug was a scientist working for a demon named Black hat (Jefecito)

Black hat and White hat are brothers
while
Dr Flug and Dr Slug are cousins

White hat invited Black hat and Dr Flug for a reunion. Somehow Both hats found out. That Dr Flug and Slug worked somewhere else before them. Their boss was abusive. That's why they left
.They had another cousin who was trapped there. And they were planning on saving him.

What they didn't know that their cousin changed into something worse

(Just read the chapters. I can't explain it properly)