|Given Name||Elsie O'Brien|
|Faction||Kitana's gang (formerly)|
Elsie O'Brien is a character in Skulduggery Pleasant: Kingdom of the Wicked. Elsie, along with her secondary school friends Kitana Kellaway , Doran Purcell and Sean Mackin , are given incredibly powerful magic from Argeddion, as a test to begin giving all mortals in the world magic.
Elsie and her friends go out regularly to practice their magic. At first, they just have fun discovering new powers they can do, but later the others become dangerous and seek revenge on everyone who has wronged them in the past, while Elsie doesn't want to hurt anyone. Doran dismembers his brother for bullying him all his life, and Elsie walks away and wants no part of the group anymore.
After Skulduggery and Valkyrie's fight with the others, Elsie is about to talk to the head construction coordinator, when she is approached by Kenny Dunne and his camera man, who ask her if she knows anything about the magic world, but she says no. She then asks the head construction coordinator, who turns out to be magic too, what really happened, and he takes her to a car where she meets Skulduggery Pleasant who takes her to the Sanctuary.
When the Sanctuary captures Sean Mackin, who she has a crush on, she tries reasoning with him to tell her where they are staying so they can capture them all, but he calls her a fat, ugly pig and Ghastly Bespoke comes in and says "Who are you calling ugly?" which intimidates him, and makes Elsie smile.
After the battle between Darquesse, Lord Vile, Sean, Kitana, Doran and Argeddion, the four teenagers lose their powers, and Kitana, Doran and Sean are locked away in prison. Elsie is a little sad and happy at the same time when she loses her powers and finds out Sean is going to jail and she is going back to her normal mortal life.