Kiyo Hikaru, a.k.a. Kidd-E. He is a Primus Corp. experiments, that Lee and Mira released and took under their wing after all the atrocities he suffered.
He is an orphan too. After being mutilated and being turned into a cyborg, Primus Corp. have injected to Kiyo the Raiju's spirit (the thunder beast), the ferocious beast merged with Aka, his imaginary and kindly friend who looks like a cat. When danger manifests and fear paralyze Kidd-E, the beast appears and offers his powers to the young boy.