Krantt, or alternatively krannt, is a krogan term for a warrior's most trusted allies, those willing to kill in his name and honor.

Krantt are often called for in rites or politics as a krogan's proxy and representative. Anybody can serve as krantt, even non-krogan. Krantt are also seen as a proof of power, as only the strongest will have warriors loyal enough to act in their name. Despite their relationship, a krantt isn't considered a servant but more like a second, or even a bodyguard of sorts. The Urdnot Shaman on Tuchanka remarks that strength in a warrior is commendable, but that they are still weak if they cannot inspire their comrades to greatness as well. A krogan undergoing the Rite of Passage is given the right to bring a krantt along not only as back-up, but as proof that they are fit to command.

Mass Effect 2

Shepard has the option of becoming Grunt's and temporarily Patriarch's krantt to assist them.

Patriarch

Shepard is sent by Aria to safeguard her predecessor as Omega's ruler from a possible hit. She wants the commander to force him into hiding, but Shepard has the option of becoming Patriarch's krantt and taking out the hit-men on his behalf, restoring his status as an authority figure in Omega.

Grunt

During Grunt's Rite of Passage into adulthood on Tuchanka, the Urdnot Shaman queries if Grunt has any krantt to aid him in the Rite. As his shipmate and commander, Shepard offers to become Grunt's krantt. The Shaman accepts Shepard, but can claim the concept is alien to humans, if the Commander states that they will help because they are Grunt's crewmates. However, if Shepard responds with confident aggression, the Shaman will believe Shepard understands the concept despite being an alien. He states that even those who are not the strongest warriors themselves can still inspire loyalty in others, drawing strength from them.