Roko is a Sangheili character who very adamantly believed in the Covenant. He was not easy to turn aside from his cause, though he eventually did so reluctantly. He is a friend to Tkan 'Zydaree, though the two occasionally experience uneasy circumstances with one another.

Your tone should refelct a character who carries extreme self-doubt and supressed hatred, though it shouldn't be too obvious. The character needs to be hard to read amongst his friends and allies, and incredibly unpredictable.