Tenris was the Seal Clan mage, who had severe injuries from the great fire.
He led Torak to believe that he was kind and knew a cure for the sickness which was going round, although later on Torak found that Tenris himself had started the sickness.
He made up a cure, which was fake of course.
He was planning on eating Torak's heart to become a spirit walker himself and almost succeded but Renn stopped him by shooting his hand.
He was killed by a Killer Whale or a 'hunter'.
it was later revealed that Tenris spread the sickness through the Juniper Berries and tested the sickness on Bale's younger brother, which had killed him
It was also said multiple times that he was handsome. It was also found that Tenris was Torak's fa's brother