Board Thread:General Discussion/@comment-71.90.156.176-20150727171348/@comment-14.98.110.81-20160605210445

Well Rachel said this to Khun before Yura Ha teleported them away in the last arc, that if they go to the floor of Death, they might find another 'Thorn' there and just might be able to figure out Baam's true identity. She also adds that she herself wants to know who Baam really is!

This suggests that Rachel does know something about Baam because of the past they shared but there's a lot she doesn't know. I personally don't think that Baam is Colorless December. If you ask me, HwaRyun warning Ehwa to stop digging too much on Ja Wangnan unless she wants to discover the worst mistake Zahard and !0 families had made seems to be a better hint for your theory.