So I was brain storming in the wake of Rise of Iron and I came up with this theory. At the moment, we know that Jolder, Saladin and the Iron Lords fought SIVA in the depths of Earth but in the end all died except Saladin. Now, the various trailers and cinematic all show a Female Titan (probably Jolder) who seals herself and SIVA away in a Warmind Vault of sorts. Under the pretense that centuries have passed since the battle, one can't begin to guess what could have happened in that vault. We've seen what the Fallen have done with it, but what if maybe SIVA modified Human tissue and corrupted it. What if the Final boss in Rise of Iron is a SIVA-corrupted Jolder?! Just a thought, let me know what you think or if I missed any important details.