Asmodeus is an alien, but he wants to save Earth.
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Asmodeus is a silly little alien.
His daily life in Gotham: when he's hungry, he eats some criminals, when he's tired, he takes a nap anywhere, being a housewife during the day, and eating at the buffet at night.
He inexplicably found himself called the "Midnight Slayer" by Gothamites.
Asmodeus: Huh?
The other criminals are petrified when Batman appears behind him.
Asmodeus: Do you also come out to eat in the dark? Don't be afraid, I'll protect you!
Asmodeus is determined to deal with Batman's little brother.
An excellent big brother decides to be a good guy - start by eating more bad guys!
Motto: Anyone can be a hero