There are three bands named Triskele, one is black metal from Canada, another is an Estonian folk group, and the other is an NSBM group from Scotland. The Estonian Triskele started its activities in 1997 with the aim to perform Estonian folk music, concentrating on ancient runesongs and folk hymns.
There seem to be more than 1 artists that go by the name of Morrigan 1. A German Black Metal band, formed by ex-members of Mayhemic Truth. See here for the band's biography.
2. A Japanese solo artist who works with the "WAVE" doujin circle. Mainly produces touhou arranges.
3. A German (Fulda, Hesse) Melodic Power Metal band formed in 1997,now split-up.(http://www.metal-archives.com/band.php?id=1667)
4. A vocal trio from Seattle specializing in nautical songs.