Eevul

Eevul, the Banshee.
First appeared in Season 2.
Season 2
After Fionn had killed St Patrick, and helped retrieve Lugh's horse Gaire from the Fomorians, he dined with The Tuatha at Tara Hill for a second, more hospitable time. Until their feast was disturbed by wailing outside.
The Banshee, Eevul, was there for Fionn. Pointing at him she said that death would come for those he loves. She promptly left like a scream on the wind.