Board Thread:Question and Answer/@comment-76.68.235.198-20150325235844/@comment-25913454-20150326024942

It's all RNG, there's not an exact percentage or anything. The only exact thing is getting the F/AW with full hearts. Altho for AW, it is estimated to be around 1 drop per 100 kills, again that's not exact and varies. Some players manage to get 5 drops with 100 kills, other manage to only get 1 with 300 kills. The only way is just to keep killing and hope for the best