Fury of Titan
Each time a unit from your army is set up using the Deep Strike ability, until the end of the turn, each time a model in that unit makes an attack, re-roll a Hit roll of 1 and re-roll a Wound roll of 1. Two details are worth reading precisely. First, it says a unit from your army rather than a Grey Knights unit, so anything in your list with Deep Strike benefits. Second, and more important, it keys off the Deep Strike ability specifically, not off the Gate of Infinity army rule's ingress move. Those are different things: a unit returning via the army rule makes an ingress move, which is not the same as being set up using Deep Strike, so do not assume the army rule feeds this detachment automatically. The bonus also lasts until the end of the turn rather than only for the first attack, which means a unit that arrives, shoots and then fights gets it in both phases.