Urdnot Wreav

Urdnot Wreav is the current leader of clan Urdnot if Wrex was slain on Virmire, and is Wrex's broodbrother, both of them having shared the same mother. He is very thankful to Commander Shepard for killing his brother, as it has led to him becoming leader of the Urdnot Clan.

Urdnot Wreav is voiced by Jim Cummings.

Mass Effect 2
After completing Grunt's loyalty quest, he happily allows Grunt to join his clan.

Wreav is a traditional krogan, preferring war to peace, and doesn't have as much trouble as Wrex would have had with Gatatog Uvenk.

Mass Effect 3
If Wrex is clan leader, Shepard will meet Wreav for the first time in the Hollows, the sacred neutral ground for all krogan, during their attempts to cure the genophage. Wreav objects to the presence of Mordin Solus, even when it is mentioned that he was going to cure the genophage, until Wrex headbutted him.

During the land assault against the Shroud facility, where a Reaper was standing guard, Wreav's tomkah was sunk by a thresher maw. Wrex believed that he was good as dead.

If Wreav is clan leader, he is a much more traditional and aggressive krogan leader than Wrex is. For example, while Wrex is about as respectful to Eve as a krogan male can be to a krogan female, Wreav treats Eve as his property and thinks of Eve as a "nag" otherwise. His place as second-in-cmmand is filled by Jorgal Thurak.

Also, Wreav's strategy for negotiations with the galaxy at large is to use force and intimidation as useful tools; if he threatens to have his krogan forces pay an alien planet a visit, for example, he doesn't have to actually follow through, knowing that merely the threat of krogan invasion will force others to listen and take the krogans seriously.

He is constantly seeking to turn situations to his vested advantage or the vested advantage of the krogan; once the genophage is cured, for example, Wreav immediately takes the credit for it and spreads stories across Tuchanka of the day Wreav cured the genophage, which Wreav knows will cause all krogan to immediately respect him as the ultimate authority. Even when Wreav's forces show up at the final battle on Earth, Wreav can be overheard giving his krogan orders to cooperate with the other alien forces but to use this opportunity to study their tactics and formations just in case the krogan ever decide to give the alien planets a visit.

If Shepard allows the genophage cure to be sabotaged by the salarians, and if Wreav is the Urdnot leader instead of Wrex, Wreav never discovers that the genophage cure is a fake, and will be successfully fooled into pledging krogan support, thus allowing Shepard to receive the "Salarian 1st Fleet" war asset exclusive to Shepards who side with the salarians and leave the genophage cure a fake, but also retain the support of "Krogan Clans" score and "Clan Urdnot" War Assets.