Fans of the Mass Effect franchise believe that there is “no reason” for Grunt not to return in Mass Effect 4, who first appeared in Mass Effect 2.
A reddit post cited many reasons why Grunt should return in Mass Effect 4. The main reason is that krogans in Mass Effect live up to a thousand years. Grunt, born in an incubator, is only about 20 biological years old, and it is quite possible that he will live to see the events of the new game. The user also points out that according to Bioware statistics, Grunt almost never dies in the Mass Effect 2 suicide mission, and is just as hard to kill in Mass Effect 3.
Other thread members generally agreed with the idea, with many feeling that his return is practically necessary as a bridge to the krogan world in the post-Shepard Mass Effect galaxy. Granted, Grunt played an interesting role in the early Mass Effect games, but at times his role was almost supplanted by other more important krogan like the Wrex and Eve. Grunt’s return to the game would allow him to play an important role in the franchise’s story.