ok, i know this may be far fetched, but after reading this thread, it got me thinking that Xigbar knows about the past and that fight, maybe he was there, maybe he was Dark Soldier? like, u see the acrobatics preformed by DS and i see that the body looks similar to that of Xigbar, maybe DS was Xigbar or possibly his somebody? flame if u must, its just that got me thinking that it maybe this way.