According to records, Talamour was a very ancient demon, reported to have been in the world forever. Jumping from body to body, Talamour sought to find a permanent host, "the right one", a body that would house it forever. However, Talamour's modus operandi for taking over a host body involved the evisceration of the victim, a process which killed the host.
By 1999, Talamour was present in Los Angeles. Its hunting ground was D'Oblique, a bar frequented by lonely singles trying to make a connection. Talamour's victims included Heather Nolan, a 24 years old paralegal who was reported missing, and 28 years old Martin Haber, whose body was found in a dumpster. The deaths and disappearances drew the attention of LAPD detective Kate Lockley, who suspected a serial killer. Allen Francis Doyle experienced a vision that put Angel on the demon's track.
The first night Angel Investigations scouted the bar, Talamour seduced a young, shy woman called Sharon Reichler, who was smitten by the demon's words, as well as its host body: Kevin. That same night, the two had sex, and the next morning Talamour jumped from Kevin's body into Sharon's, killing her instantly.
Talamour next target was Neil, a geeky, insecure young man who was instantly attracted to Sharon's looks. Neil also spent the night with "Sharon", though the experience was pleasant for neither of them. Not even waiting until the next morning, Talamour ordered Neil, who was lying in bed, to turn around. Talamour left Sharon's body, and jumped into Neil. As Talamour finished the process of taking over Neil, Angel entered Neil's apartment and confronted the demon.
After a brief fight, Talamour escaped the apartment through a window, leaving the defeated Angel to confront Kate Lockley. Upon seeing Angel in the same room as Sharon's eviscerated body, Kate believed Angel was the serial killer she had been after. In Neil's body, Talamour seduced another woman. Afterwards, Talamour ended up in the body of Danny, the bartender of D'Oblique.
While in Danny's body, Talamour set out to find its next victim and approached Kate. She inquired him about Angel, who had helped Danny stop a fight days before. As Talamour knew its time within Danny was running short, it told Kate that Angel was in the alley behind the bar, much to Kate's surprise. The two went together and as Kate told Danny to call her sergeant and ask for backup, Talamour smashed a wine bottle over her head, leaving her unconscious.
Talamour prepared to rape and possess Kate, only to be attacked by Angel. The two fought for a short time, until Talamour noticed that Danny's body would begin to fall apart, as the host body received an injury that didn't heal. As Danny's skin began to fall off, Talamour returned to the bar, desperate to find someone. However, the host body's appeareance caused instant rejection, disgust and fear in the women Talamour approached. Unable to connect, Talamour grabbed a woman and forced her to another alley.
Angel saved the girl in time fought the demon for a third time. Talamour was able to hold its own against the vampire, fiercely fighting him and resisting his attacks. However, during the fight, Angel managed to throw Talamour to a burning barrel used by a pair of homeless people to keep warm. Danny's body instantly catched on fire, though Talamour still attempted to attack Angel. However, Kate shot repeatedly at the flame covered body, until it was incapacitated. Talamour was killed by the flames.
Afterwards, all the deaths caused by Talamour were pinned on Danny. Kate came to the conclussion that he was the serial killer because, as D'Oblique's bartender, he each and every one of the victims. Unable to tell her the truth about Talamour in particular, and demons in general, Angel agreed with Kate.