After over 1000 years of aimless apathy, Wrex seeks to bring back hope to his people and reverse their fate by undoing the genophage.

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.

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.

If the player imports a Mass Effect save where Wrex was recruited and is still alive, he will appear on the krogan homeworld of Tuchanka and greet Shepard warmly on arrival.

[11] Alternatively, if the player imports a save where Wrex died or was not recruited, his more bloodthirsty traditionalist half-brother Wreav will appear in his stead.

Wrex remains on board the Normandy while the salarian scientist (Mordin or Padok Wiks) synthesize a cure from their tissues.

In the Citadel downloadable content, he becomes a party member for the DLC's duration, provided he is alive and Shepard chose to cure the genophage.

[6] If a save is imported where Wrex was killed at the stand off in Virmine in Mass Effect, his role will be replaced by his broodbrother, Urdnot Wreav.

Unlike Wrex, Wreav will not be smart enough to see through the deception, and if Maelon's data was erased, resulting in Eve's death, Mordin can be convinced to allow for the cure's sabotage.

Prior to the release of the first game, Ray Muzyka, CEO of BioWare, believed that Wrex would prove one of the more popular squadmates.

[14] Tom Francis, writing for PC Gamer, wanted to see Wrex most out of all returning characters in Mass Effect 3, noting his popularity in how him simply saying "Shepard" had become a meme.

Official Xbox Magazine awarded him "Sidekick of the Year", saying "Brilliant dialogue, pitch-perfect voice acting, and incredible comic timing made Wrex the most charming, fun, and just plain cool giant armored lizard we’ve ever (virtually) met.

"[19] VideoGamer.com's list of "Top 10 Video Game Companions" placed him seventh and called him their favourite Mass Effect character, noting the humour in his bloodlust.

[20] Adam Biessener of Game Informer listed him second in his "The Top 5 Wingmen Of The Decade" article, commenting how his quality of writing separated him from other stereotypical "brusiers".

[22] Similarly Steven Hopper, for IGN, listed him as the third best squadmate in the Mass Effect games, calling him "stubborn" and "tough as nails".

[25] Green Man Gaming included Wrex in their top 5 list of the best characters from the Mass Effect franchise.

He compared his experience of both scenarios as follows: "I was kind of happy but bored by the ho-hum nature of Wrex's survival, while on the other I was shocked and emotionally moved, yet saddened, by his death."

[30] PC Gamer staff member Chris Livingstone claimed that the only time he undid one of Mass Effect’s events in his playthroughs was, "in the first game, when an argument led to—shockingly, and I thought, unfairly—Wrex being shot dead in a cutscene.