Savella is one of the main antagonsits, and final antagonist, of the vampire film, Byzantium, along with Captain Ruthven. He is a master vampire, who is hunting down the mother and daughter protagonists of the film, Carla and Eleanor, which he spent two centuries doing.
As revealed in the flashbacks of the film, Savella is the leader of the Brethren,a secret society of vampires which protect the secret of vampirism, their members have traditionally been male noblemen. At some point a Naval midshipman named Darvell has become a vampire after being saved by the Brethren, taken to and island, and has since joined their ranks. Darvell meets with his old captain, Ruthven and offers him a chance to become a vampire himself, but one of Ruthven's prostitutes, Calra cheats Ruthven out of immortality, and heads to the island herself.
Darvell finds Clara and takes her to the Brethren, and they take great offence that low-born woman, prostitute has joined their ranks, but they decide not to execute her as she hasn't broken any of their rules, but exile her after warning her she is not to take part in their brotherhood. Despite this, after Ruthven infects Carla's daughter Eleanor with syphilis, she turns her daughter into a vampire, and they become targets of the Brethren.
Two centuries later, one of the brethren, Werner, encounters Carla at a lap dance club she works at. She kills Werner and flees with her daughter.
They seek refuge with a man named Noel, the heir to Byzantium Hotel, which is down on its luck. Having seduced Noel, Clara turns the Byzantium into a makeshift brothel and Eleanor joins the local college with Frank, a young man she has befriended. Interested in her past, Frank questions Eleanor, who writes her story for him to read. Not entirely believing it, he shows it to their teacher, Kevin.
Eleanor has fallen in love with Frank and decides to help him turn into a vampire so they can be together, since he is dying from leukaemia. Before killing him, Clara finds out from Kevin that Eleanor has told Frank of their past. Noel is accidentally killed as Clara tries to prevent Eleanor from leaving the hotel and succeeds in locking her in the lift. While Clara is out dealing with Frank, Darvell and Savella, posing as policemen, find out from Kevin's colleague Morag where Clara is and go to kill her. Clara leaves without killing Frank when she realises that Eleanor is in mortal danger.
They kidnap Eleanor and drive her to an abandoned location with the intention of destroying her, only to be stopped by Clara. After killing Morag, Savella battles Clara and ultimately subdues her. Savella hands Darvell his sword (which he took from Byzantium during the Crusades) so he can kill Clara. However, Darvell, who has always harboured feelings for Clara, kills Savella instead.