This September, the secrets of the greatest champion for mutant/human relations come to light in the oversized UNCANNY X-MEN #25 - the shocking finale of The Last Will & Testament of Charles Xavier! Superstar creators Brian Michael Bendis & Chris Bachalo unearth a devastating secret of their former mentor that will send shockwaves through both camps of X-Men! What has Xavier been hiding? A mutant so powerful their very existence was a threat to mutant's way of life. A destructive force so powerful they would've wiped out any chance of a peaceful coexistence between humans and mutants. An unstoppable power now unleashed in the wake of Xavier's death! Against such overwhelming power, the splintered squads of X-Men must unite if they have any hope of stopping it. And the story of how it came to be will cast a new light on their beloved teacher - and the depths he would go to protect mutant/human relations. Witness Xavier's final "gift" to his children, but will it be their undoing? Find out when The Last Will & Testament of Charles Xavier comes to its staggering conclusion in UNCANNY X-MEN #25!