Adelia was a Priestess who worshipped Lymilark. She used to work in Tir Chonaill, before Meven and Endelyon, at a time where the town constantly had to fend off attacks. She was friends with Isla, the Pontiff of that time.
She eventually sacrificed herself to save Tir Chonaill's inhabitants.
After her death, she was canonised as a Saint and the stream flowing through Tir Chonaill was renamed after her.