Happy is a blue, cat-like alien from the planet Exceed. He's a character from Hiro Mashima's Fairy Tail series, though he shows up in the spin-off as Rebecca's sidekick.
The tragic part of his backstory is that he died in a car accident when Rebecca was a kid. Professor Weisz brought him back by putting his consciousness into a mechanical body. From that point on, Happy stuck with Rebecca as her loyal companion, and he's pretty central to how she fights—he can literally transform into a pair of guns called the Happy Blasters, which Rebecca uses to fire non-lethal ether bullets at enemies.
Content compiled by AnimeList.moe from publicly available sources.
