Spike

Spike is a vampire in Jossverse. He appears in the TV shows Buffy the Vampire Slayer and Angel.

In canon
Spike is a bad boy and once set himself the mission to kill Slayers.

In fanfiction
By many fans Spike is thought of as a sex god, something which he probably would not deny himself.

Because Spike was very friendly with Angel (before the latter got his soul back), and is known to have been part of his "family" (sometimes known as the "fanged four") back in the bad old days of victorian England it is assumed by many writers that the two were (and are) lovers. Spike usually playes the role of Uke in this relationship. Some Spike/Angel Slash is goodfic, but a vast quantity is badslash featuring PWP rape and Dubious lube.