Astonishing X-Men: A Man Called X

The Shadow King has been defeated and Professor Xavier has returned, reborn in the body of Fantomex. Has his time imprisoned on the astral panel fundamentally changed him — and if so, is it for the better or for worse? But before they can discover exactly what kind of man he has become, the X-Men must face another creature who has been resurrected alongside Xavier — the supremely powerful reality-altering mutant Proteus!