My Little Demon Pet, the Divine Lord

She went out to buy groceries and "picked up" a cat. Not only did it come right to her doorstep, it could also understand human speech. It helps her teach a scumbag a lesson and saves her life. Best of all, it can even turn into a human...

"I can only become human at night. As long as you don't let anyone find out... Besides, we've already made a pact. If I'm separated from you, I'll grow weak and die."

Well-behaved, adorable, and begging to be taken in: how could anyone not love a cat like this?