A famous bounty hunter and mercenary, Wrex is among the last of the Krogan Battle Masters. They are rare individuals who can combine biotic abilities with advanced weaponry and tactics. He joins the crew of the "SSV Normandy" in the first "Mass Effect" to hunt the rogue Spectre Saren, but is later drawn into a stand-off with Commander Shepard in Virmire when he discovers that Saren's scientists have uncovered a cure for the genophage. Depending on the outcome, he may return in later sequels and eventually become a leader of the krogan.