I don’t recall this character.
According to the IC wiki:
Otvek was an Urgal whom Eragon searched his memories for evidence of treachery against the Varden.
Four of the Kull were searched by Eragon; Garzhvog, Khagra, Otvek and one other. During the Battle of the Burning Plains, two of these Kull fell in battle. Since Garzhvog and Khagra are both still alive, it is assumed that Otvek and the other were the ones to fall.