Originally Posted by
BobbysWorld
Well to tie it back into Spurrier's Krakoan work specifically, Onslaught is gone now, but there's always the potential to say that while Onslaught was sneaking around undetected, it was able to use its influence over Xavier and affinity for the 'weak spots' of the resurrection protocols that were vulnerable to him and like.....sow a few seeds of potential longterm chaos or contingencies in case it was ever discovered or ousted. Like maybe they discover that there are specific cases or instances where Onslaught sabotaged a resurrection or interfered with one with specific intentions....such as making Xavier think he was putting Hank's back-up into his new husk when actually Onslaught had made him unknowingly swap it out for Dark Beast's. Or editing out key details or information from various mutants' minds so that people assume them to have a certain view or knowledge about events or other characters, with no idea there's a deliberately carved out blindspot in those mutants' memories or history instead. That kinda thing.
(And of course, it IS worth noting that the time Dark Beast replaced Hank without anyone else knowing just so happens to have taken place during the original Onslaught storyline. With Onslaught, even as he was still masquerading as Xavier to everyone else, being the only one to notice the swap and realize who Dark Beast really was, and then recruiting him as his minion while both continued to hide their true natures from the rest of the X-Men. Thus its actually a very feasible callback for both characters and makes tons of in story sense for Onslaught to have swapped an established former minion of his into the heart of Krakoan infrastructure while he had total unobstructed access).