Sedris

Sedris, a.k.a. The Traitor King is the most powerful lich on the former Shard of Alara known as Grixis.

History
Before Alara was sundered into the Shards, there existed a kingdom named Vithia. Much like the kingdoms that make up the Shard of Bant, Vithia functioned on a similar system of castes and had a focus on knighthood and chivalry up until the sundering occurred.

When Grixis was separated from the rest of Alara and cut off from white and green mana, the demons and necromancers gained power in the ensuing chaos. However, even though the powers of Vithia's mages were losing their potency, there was still a chance for the kingdom to survive, due to the martial skill of its many knights.

Sedris was once the good and righteous king of Vithia during the early years following the sundering. It is unknown when exactly he fell from grace, but when demons tempted him with dreams of power, he submitted. Sedris handed thousands of innocents over to the demons, killed his own family and advisors, and performed a dark ritual that allowed his consciousness to continue into unlife.

Vithia's paladins, unable to stop the fallen monarch, fled the kingdom, the ancient Vithian word for traitor - Grixis - on their lips.

Vithia was overrun by demons and the undead shortly afterwards, and the capital was transformed into Sedraxis, the now greatest necropolis on the plane. Sedris still rules this dark city of the dead, as the most powerful lich warlord on the plane.