User blog comment:Angren Túrë/When's the Darkness gonna show up?/@comment-4010415-20151102194138

Like Phantomlink said, a lot of the stuff they had planned for Volume 2 had to be pushed to Volume 3.

In Free Play #22, Miles and Kerry said that Volume 3 is the start of RWBY turning dark. In terms of darkness and maturity, they said it's like having Harry Potter skip books 2-5.