Caelan is a vampire in the Skulduggery Pleasant book series. He serves as a supporting protagonist in Dark Days and Mortal Coil and a neutral character-turned-the hidden final antagonist of Death Bringer, due to developing an obsession with Valkyrie Cain.
Initially appearing to organise a meeting with Thames Chabon on her quest to retrieve the head of Skulduggery Pleasant, Caelan later saves Valkyrie from Dusk after she is bitten by him at Croke Park Stadium. She then offers him to have a taste of his blood and after he does, he begins to claim that the two of them are meant for each other and that he loves her, though she keeps insisting that he merely thinks he does. Despite numerous warnings from Skulduggery and others that she shouldn't involve herself with Caelan, Valkyrie nonetheless continues to see Caelan(behind her boyfriend Fletcher Renn's back, though she never sees it as going out with him), but quickly becomes sick of him because of his tendency to blame himself for everything that happens to her and his uncontrollable obsession with her, to the point that he proposes to her out of the blue. However, when she tries to break up with him, he refuses to accept it and attempts to turn her into a vampire, before Fletcher(now broken up with her) comes to her rescue and together the two kill him by drowning him in salt water.
- Caelan is similar to Carmilla from the Castlevania: Lords of Shadow games. Both are vampires who develop an obsession with the main protagonist, get angry when the hero rejects them and go so far as to attempt to turn them into their slaves. The main difference is that Carmilla is far more serious and cunning.