Wait, if Grunt is considered a "violent and unpredictable Krogan," then what would Wrex be? Following the earlier reveal of "deadly assassin" Thane, BioWare has announced the second new character in the Mass Effect 2 squad: Grunt, "a blood-hungry Krogan." (Blood ... hungry? Is that worse than blood-thirsty?). In this announcement, BioWare is really pushing the cause and effect nature of your squad selection: "The success of the mission hinges on the squad recruited and their loyalty to the mission. Shepard's future depends on it."
BioWare's Ray Muzyka -- referring to the series very clearly as a "trilogy" –- says, "Building out a diverse and loyal party is one of the features that makes the Mass Effect series quite unique. The characters Commander Shepard recruits are not only pivotal to the storyline, but essential to the player's overall success." So, Grunt: On the one hand, he possesses "unsurpassed physical strength." On the other hand ... he eats blood. It's a tricky balance.