The TW Network
 Yuu Yuu Hakusho Fighters
Fighter ID:
 Password
Full Name
Raizen Toshin

Games
Yū Yū Hakusho Dai-Yon-Dan
Game Boy
 Highlight Enki at the Character Select screen, hold Select and B, and press Right.
Yū Yū Hakusho Final
Super NES
Yū Yū Hakusho Forever
Playstation 2

Storyline
Yū Yū Hakusho Dai-Yon-Dan
Background
Yusuke Urameshi
Descendant
Though related, the exactly nature is either ancient or otherwise indeterminate.