Colonel Lennok was the second-in-command of the Venek Horde when it laid siege to the Jocacean Monastery, serving under General Grines. Though he was highly aggressive, like other Veneks, Lennok did have a measure of self-control.
When Lennok discovered Grines had died, he was understanding -- though he was offended to find his body dressed in the clothing of a nurse, as he was unaware that this had been part of Grines' attempts to escape the monastery.
When John Crichton and the other time travelers fled back to their own time, Lennok led the Venek Horde into the monastery to hunt for the Peacekeeper forces -- which had departed. With the bloodlust upon the horde, Lennok could not prevent them from slaughtering all of the women and children within the monastery.
Lennok is derived from Farscape.