He appears first as a ex-Reigner who was in 'stass sleep' but revived by the Bannus. He is released from his [stass tomb]? by Ann Stavely. Together, they create Hume? from their infused blood with help from the Bannus. Mordion, Hume? and Yam live for a considerable part of the book in the woods.
Mordion has camel coloured hair, wears a robe of the same colour and carries a staff. He has a pleasant voice, with a slightly foreign accent. His eyes are blue and sunken in and his eyebrows meet at a point above his nose. He is also, in contrast to his 'Grim Reaper' appearance, the owner of the most beautiful smile in the world.
Mordion has an interesting personal history (see Hexwood (spoilers)).