WARNING: The following contains spoilers for X of Swords: Creation by Jonathan Hickman, Tini Howard, Pepe Larraz, Marte Gracia, & VC's Clayton Cowles, on sale now.

Apocalypse has always been one of Marvel's strongest mutants, so it always made sense that any of his direct descendants would be equally as powerful, if not more so. And in X of Swords: Creation #1, Apocalypse's grandchild, Summoner, demonstrates just dangerous someone with his bloodline can be by killing the young X-Man, Rockslide.

With one swift blow, Summoner may have effortlessly cut Rockslide apart, but he could not do that right off the bat. To add insult to injury, the Summoner posed as the young X-Man's friends to learn about his weaknesses before his brutal attack.

RELATED: X-Men Reveals the True Reason Apocalypse Is Working With the Heroes

Summoner began studying Rockslide at the beginning of Jonathan Hickman and Leinil Francis Yu's X-Men #12, playing an Arakko game with the young mutant that allowed both players to discover the weaknesses of their opponent. It was almost akin to a game of chess as the two of them studied one another, pointing out what weaknesses they could find. In Summoner's case, his weakness was his eyes, the only part of him that didn't seem to inherit Apocalypse's invulnerability. While studying Rockslide, Summoner comes to the conclusion that the reason Rockslide is effectively immortal is because his rocky exterior is essentially a shell that protects his inner energy, which is where his true essence lies. As long as that inner energy remains uninjured, Rockslide can recover from whatever befalls his earthly form.

In Rockslide's defense, Summoner calls this a vulnerability, not a weakness. He implies that if someone knew how to attack Rockslide, then it would be easier to take him down. But Summoner never once suggested or even postulated that there was a way to get rid of the psionic energy within Rockslide.

RELATED: X-Men: Apocalypse Sent Two Classic Mutants on a VITAL Mission for Krakoa

Of course, it remains unclear whether or not the Summoner exploited this vulnerability or merely attacked Rockslide's physical form. In X of Swords: Creation #1, Rockslide accompanies Summoner, Apocalypse, and a few other X-Men through the External Gate to Otherworld so that they can rescue their captured friend, Unus. But once the X-Men see that Unus' captors are the First Horsemen, Apocalypse's children, Summoner betrays them, attacking his grandfather with help from the Horsemen. Hurt by this betrayal, Rockslide attacks Summoner, who mentions the game they played earlier before he conjures a sword and slashes clean through Rockslide.

Among other things, this hints just how strong the Summoner truly is. Before, it was believed that he could only summon the dark beasts of Arakko like daemons or even elemental monsters. However, this short battle with Rockslide indicates that his abilities are far more versatile than merely conjuring something else to do his bidding. By creating a blade capable of piercing through Rockslide's skin he demonstrated not only skills in melee combat, but also an enhanced strength as he cleaved Rockslide in half.

RELATED: X-Men: Two Major Heroes Help Apocalypse Accomplish the Impossible

This feat alone is enough to signify what a threat he is. Rockslide has been capable of falling from great heights, withstanding large amounts of heat and pressure, but all it took was one swing from Summoner's sword and Rockslide was cut through like warm butter.

What's even more worrying is the fact that Rockslide did not reform after this happened. Since he first appeared in Nunzio DeFilippis, Christina Weir and Carlo Barberi's New Mutants #3, he has been able to split apart and continue fighting, but Summoner's attack seemingly did enough harm to take Rockslide out of commission, semi-permanently. Despite all this, the X-Men who Rockslide traveled with did not seem too distraught by what happened, which implies that Rockslide may return through Krakoa's resurrection protocols. And when he does return, this young X-Man could very well take advantage of the Summoner's vulnerability.

KEEP READING: X-Men: Marvel Confirms the Externals Are the Mutant Illuminati