If Urdnot Wrex was killed on Virmire, Urdnot Wreav will lead Clan Urdnot and will call all krogan clans to the Hollows on Tuchanka, where Thurak and two other krogan members of the Blood Pack will be present. He is first heard giving warning to Wreav of the Reapers attacking the Hollows as the Urdnot leader's Tomkah pulls up.
Upon seeing either Mordin Solus or Padok Wiks, Thurak will immediately object to his presence, not willing to let what the salarians did to the krogan be forgotten. This leads to an argument, with Thurak stating that Clan Jorgal has been around since there have been krogan, saying Clan Urdnot does not have their collective experience or the wisdom of Thurak alone that you cannot trust a salarian. Wreav says that the reckoning for the genophage will be when he says so and Thurak pulls out his shotgun on the Urdnot leader, but is interrupted by Eve.
After a rallying of the krogan, Thurak becomes part of the convoy that will initiate the groundside attack on the Reaper and his Tomkah is one of two left standing after a turian fighter gets shot down and lands on top of the convoy. Thurak later covers Wreav as he picks up Shepard and the Commander's squad, but he is sucked beneath the earth in his Tomkah by Kalros, the mother of all Thresher Maws, and presumed dead.
If Wrex survived Virmire, Thurak's role will be filled by Wreav and the other Blood Pack members will follow him.