I think its not hard to get 1b++ damage on bow rouge. Even a level 30 toon with magic equip can do that. The trick is you have to gather enemies closer. I mean lot of them, preferably melee… Then make sure you have added a skill points on guidedshot… Then when you fire the shot… Every pierce on enemy adds damage depending on your damage per pierce on guidedshot rank level… When your damage outreach billions the number indication will be… 123564785 damage