Mordred

Mordred is an anomay in the Brotherhood of Souls cycles, his place is not known however what is known is he brought the Brotherhood of Souls it's first defeat and was thereafter branded as the Eternal Traitor.

In the current cycle he has been reborn again and was saved from death at the hands of Arthos (Fionn) by Tristan and Commodore Strathmore.

However it was stated by Merlin that in the newest Cycle that Mordred was changed by Merlin and that he dosen't know how he'll turn out this time.

It transpires in a possible future that Mordred lives up to his title.

He sends the Brotherhood of Souls on a fake mission using his influence with the people who trust him. Leading them into a massive vampire ambush, everyone but Arthos (Fionn) is killed, Arthos (Fionn) is captured and kept as a pet so the cycle can't restart.

After this Mordred also kills Magnus and is hailed as the hero of the shards, then handing over the rulership of the world to Apocolypse.