Kaen Sokai
Riyo and Hiei's only son and second child (is thirteen years younger than Sachi). While he really enjoys learning new techniques and abilities to use his energy on (particularly since it means getting to spend quality time with either of his parents and sister), Kaen is very unlike the rest of his family and isn't all that interested in fighting (taking part or watching). Having been raised in the human world all his life (unlike his older sister, whom spent a chunk of her own childhood in demon world), he just wants to lead a regular and peaceful life (as close as he can get as someone that's only 1 quarter human, anyway).
Is a lot like his mother in that he's quick to want to make friends with just about anyone he meets.