Wrex makes his debut appearance in 2007's Mass Effect. A bounty hunter, Wrex is hired by the Shadow Broker to assassinate Fist, a former agent who had defected to the rogue Council Spectre, Saren. Wrex is first seen trying to intimidate his way through Chora's Den, where Fist is based, but is unsuccessful. Later, Commander Shepard meets with Wrex, looking for Fist as well. Wrex agrees to join Shepard, since they share a common goal. When Fist is found, after he tells them that he sent a quarian who had information on Saren to meet with agents of the Shadow Broker, who were going to kill her, Wrex fulfills his contract by killing Fist. After a brief reprimand from Shepard, they then invite Wrex to join their team, which he accepts, and spends his time in the cargo bay of the Normandy. In conversations with Shepard, Wrex talks about how he used to be a "Battle Master", which holds him in high regard in the krogan military, but the constant wars between the clans of the krogan homeworld, Tuchanka, brought forth by the genophage, caused him to leave, with the final straw being that Wrex's own father tried to kill him. Wrex also reveals that he was hired by Saren before, but during the mission with him, Wrex felt uneasy about Saren and left. Wrex's uneasiness with Saren proved accurate, as everyone else that Saren had hired for the mission ended up dead.
