Board Thread:General Discussion/@comment-26395021-20150627041524/@comment-14909251-20150630232655

VedranTheII wrote: It’s more or less the manifestation of willpower, so aura but limited to badasses. They are not that different. Anyone can develop Haki and it is essentially a manifestation of one's spirit. On Amazon Lily, lots of the women who are otherwise weak have Haki. When even Usopp has Haki, you know it isn't strictly about strength. In that way it is probably harder to develop Haki than Aura, but they are very similar in nature aside from that. Granted, there has been no indication that anything akin to Haoshoku Haki exists in the RWBY world, similar to how there is no Haki equivalent to Semblance, but you can definitely get a sense of the more basic similarities.