Got Gjallarhorn randomly in crucible very early on, probably like 2nd or 3rd week that Destiny was out. Then I was away for 2 months without my PS4 or an internet connection. When I came back I was without a new exotic for a few weeks before I finally got the exotic bounty for Invective and got it in only a few hours. I consider that my real first exotic, since Gjallarhorn I've mostly only ever used for bosses, plus it's the old version stuck at a 300 max attack rating, and the way I got it was entirely RNG.