Mass Effect 2 & Mass Effect 3
Durak is a small, heat-blasted rock lost in the blinding glare of the star Aralakh. It occasionally traps a trace atmosphere of gases blown in on Aralakh's powerful solar wind, which inevitably blows the gases back out again.
The planetoid has a few valuable lodes of heavy metals, which were sporadically mined by the krogan at the height of their power. In the closing years of the Rebellions, the five clans working the planetoid fell to fighting over a particularly rich deposit of iridium. All five clan warlords agreed to a Crush (a meeting at a neutral location) to negotiate a truce. Unfortunately, all five arrived planning to betray their fellows. While the leaders and their seconds met, all their bases were destroyed by simultaneous hypervelocity cannon strikes.
Left with only the food, water, and air in their hardsuits, and with no way to call for rescue, the warlords apparently fought each other to the death. The survivors of the five "Durak Clans" on Tuchanka still argue about which clan's warlord was the last one standing.