To Beat The Tarkh Out is a quest of the Haven playthrough in Might & Magic: Heroes Online.
The hero has to battle Tarkh-Noor in two stages. The first stage is where Tarkh-Noor attacks the hero with his own army, consisted of lesser cerberi, lesser maniacs and lesser juggernauts. After defeating them, Tarkh-Noor curses Gharokh, since he gave him "weak" troops.
In the second stage, Tarkh-Noor himself joins the fight as a boss, with 5000 hit points and with his other forces, including succubi. However, the hero, regardless of back-up troops, continues the fight, with all the losses included from the last fight. The demons have to be defeated and once they have, Tarkh is banished off to Sheogh.
Albin is pleased and recommends talking with Emperor Duncan Falcon.