Jorgal Thurak is a krogan of Clan Jorgal and also a representative of the Blood Pack.
If Urdnot Wrex was killed on Virmire or never joined Commander Shepard's mission to stop Saren Arterius, Urdnot Wreav will lead Clan Urdnot and will call all krogan clans to the Hollows on Tuchanka, where Thurak and other krogan members of the Blood Pack will be present. He is first heard giving a radio 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 the scientist's presence, not willing to let what the salarians did to the krogan be forgotten. This leads to an argument with Urdnot Wreav, with Thurak claiming that Clan Jorgal has been around since there have been krogan, and that he owns pet varren older than the "whelps" of Clan Urdnot. Wreav counters that Clan Jorgal is old and weak, but Thurak responds that Jorgal at least has the experience to know that a salarian cannot be trusted. Wreav bellows that the reckoning for the genophage will be when he says so, at which Thurak pulls out a shotgun on the Urdnot leader, but is interrupted by Eve.
After the krogan agree to rally around defeating the Reapers and curing the genophage, Thurak becomes part of the convoy that will initiate the groundside attack on the Reaper and his tomkah is one of the few still intact after a turian fighter crashes amidst the convoy after getting shot down by the Reaper Destroyer guarding the Shroud. Later, while covering Wreav as he picks up Shepard's squad, Thurak is sucked beneath the earth in his tomkah by Kalros, the "mother of all thresher maws". He is presumed dead, to the indifference of Wreav, who comments that Jorgal was "not a friend" anyway.
If Wrex survived Virmire, Thurak's role will be filled by Wreav and the other Blood Pack members will follow him.