Guarantee it'll be a quest reward. Since The Taken King, there has been somewhat of an imbalance between quests and RNG in regard to Exotic weapons. For a Year One player going into Year Two, only four new (keyword) weapons were randomly obtainable... Zhalo, Telesto, Hereafter, Jade Rabbit, the rest were all quest rewards. In Rise of Iron... Nemesis Star and Trespasser, the rest were quest rewards.