Eleceed (Manhwa) Wiki

Jiwoo is a kind-hearted young man who harnesses the lightning-quick reflexes of a cat to secretly make the world a better place – one saved little child or foster pet at a time. Kayden is a secret agent on the run who finds himself stuck in the body of a…um…decidedly fat old fluffy cat. Together, armed with Jiwoo’s superpowers and Kayden’s uber-smarts, they’re out to fight those forces who would let evil rule this world. That is, if they can stand each other long enough to get the job done.

Source: Webtoon