|Aidan of Whiteshore|
|Mother||Unnamed Lady of Whiteshore|
|Father||Lord Murtaugh of Whiteshore|
|Other relations||Rathnait (betrothed)|
|Allegiance||Inis Eala, Johnny's band, Whiteshore.|
|Residence||Inis Eala (formerly)|
At the beginning of Heir to Sevenwaters, Clodagh is in love with him, but falls out of love when she finds out from Cathal that Aidan is expected to marry another girl, Rathnait, back at Whiteshore and has been lying to her about it. Aidan seems genuinely remorseful about his actions, and tries to make it up to Clodagh.
When Finbar is taken and Cathal is accused of helping the kidnapper, Aidan doesn't believe Cathal would do such a thing, and tells Lord Sean and Johnny. He argues with Johnny when Johnny orders him to hunt Cathal, and only agrees to do as Johnny says when Johnny threatens to cast him out of his band of warriors. In the forest Aidan confronts Cathal as he and Clodagh board a raft to cross the river to the Otherworld. When Aidan sees Clodagh choose Cathal over him he stands frozen, doing nothing as Cathal and Clodagh leave.
Aidan is killed in the middle of the novel, by an evil prince of the Fair Folk, Mac Dara, who also happens to be Cathal's father. Cathal is grief-stricken over his death, as he cared about Aidan and is afraid that Aidan thought that Cathal had killed him.
Aidan is tall and broad-shouldered, with a strong-boned face, well-kept hair and friendly eyes. He bears the markings of a lark around his eye and nose.
Though Aidan is a good person at heart, he has a jealous streak, which can make him act cruelly at times. When Cathal and Aidan were nine years old, Aidan killed a dog Lord Murtagh had given Cathal as a present, because he was jealous of his father's attention on Cathal.
- Father: Murtagh of Whiteshore
- Mother: Unnamed woman
- Siblings: Cathal (foster brother)