Gai (ガイ)

Guy is Riki's second in command, best friend, and former pairing partner. He takes over Bison when Riki vanishes from Ceres.

Guy is desperately in love with Riki, whether or not Riki sees it, and this turns into a dangerous obsession with bringing Riki back to being the man he knew, no matter the consequences and whether or not this is what Riki wants.

(Source: Tanagura An Ai No Kusabi Fanlisting)