WARNING: The following contains major spoilers for Way of X #5, available now from Marvel.
Nightcrawler has long been one of the more introspective mutants among his peers, and Way of X has seen his latest journey of self-discovery become a search for a unifying mutant religion as well. Unfortunately, this has been undercut by the surprising reemergence of Onslaught, who has already sewn discord throughout Krakoa without ever truly revealing himself.
And in Way of X #5 by Si Spurrier, Bob Quinn, Java Tartaglia, Tom Muller, and VC's Clayton Cowles, Nightcrawler's battle against this impossibly powerful psionic foe has led him to make the ultimate sacrifice with a revealing hand from Marvel's most treacherous mutant, Fabian Cortez.
On Mars, Nightcrawler brought Fabian Cortez and Lost together in the hopes that they will be able to work through the horrors of their shared history. Cortez's prideful indignance and Lost's loathing of the man who killed her family already make that all but impossible, Nightcrawler's stern insistence on facing the past proves to be just what they need. However, their budding understanding is soon targeted by the influence of the psionic entity Onslaught, and their budding understanding is replaced entirely with hatred. Cortez is overcome with a need to kill and turns on Lost, all while her attention is drawn to loftier goals. All that Nightcrawler can do is watch as Cortez kills Lost by overloading her powers, and with her dying breath Lost set the moon Phobos on a collision course with the newly crowned mutant planet.
Once the gravity of the situation has set in, Cortez begs Nightcrawler to get them to safety before Arakko and Phobos are destroyed, but the veteran hero is already set on saving the world. Nightcrawler is able to convince Cortez to overload his, much like he did with Lost. While this kind of power surge is lethal, Nightcrawler is able to teleport Phobos back into its proper orbit. And as he does that, Nightcrawler is given several visions that show him how to stop Onslaught and unite Krakoa, visions that are fated to be lost in his imminent death.
Using his powers to teleport a planet easily ranks among the most impressive things that Nightcrawler has ever done, and his sacrifice marks one of the noblest. While Cortez has usually been portrayed as a deeply repugnant character who famously betrayed his mentor Magneto, even he is moved by Nightcrawler's sacrifice. Nightcrawler even trusts Cortez to be his messenger and to remind him of the things he saw in his visions. Although an Onslaught-possessed Xavier kills him before he gets the chance to finish that mission, it has a clearly transformative effect on the former Acolyte.
Through his actions, Nightcrawler found a way to save a mutant planet from complete destruction. But with what he realized in his final moments of life, he may have found a way to unite mutantkind spiritually, and he may need those lessons to take down Onslaught too, if he can remember them.