WARNING: The following contains spoilers for X of Swords: Creation by Jonathan Hickman, Tini Howard, Pepe Larraz, Marte Gracia and VC's Clayton Cowles, on sale now.
One of Marvel's first mutants, Apocalypse has played an integral role in the development of mutantkind. With his survival-of-the-fittest mentality, he has been willing to spill as much blood as necessary to ensure that mutants grew stronger in a world that wanted them dead. Often coming into conflict with the X-Men, it wasn't until the formation of Krakoa that Apocalypse saw mutants truly become powerful.
Now, as a leader and member of the Quiet Council, Apocalypse has been given the chance to examine his long history and his many actions while leading mutantkind into the future. However, Apocalypse's look back to the past in the first chapter of the X-Men's new crossover has also revealed his greatest weakness: his children.
Aside from Apocalypse's secret history with Krakoa, X of Swords hinges on En Sabah Nur's First Horsemen, which consisted of Death, War, Famine, and Pestilence. Born to his wife, Genesis, the First Horsemen were effectively his children and the most beloved of Apocalypse's legions of many servants. Although they were the strongest Horsemen to serve him, they and his wife were lost to him in the forbidden realm of Amenth on Arakko, Krakoa's sibling island. It wasn't until Apocalypse found a home on Krakoa that the opportunity arose to reach out to his children.
After coming into contact with his grandchild, the High Summoner of Arrako and sending select mutants into this forbidden dimension, Apocalypse finally took the steps to travel into the realm that had taken his family. Upon finding a destructive army surrounding Saturnyne, he was even more shocked to learn that his children had not only survived millennia in a hellscape and were leading that army towards Krakoa. In an uncharacteristic display of emotion the mutant warlord, Apocalypse actually fell to his knees and reached out to them. Upon pulling their father up, his children confessed that love was not what had motivated them to keep their sanity amid the bloodshed. War consequently stabbed her father in the chest, leaving Apocalypse critically injured and possibly dead.
This isn't the first time that a Horsemen has been considered a child of Apocalypse. When En Sabah Nur had an affair with one of his Famines, a woman by the name of Autumn Rolfson, she had a child that would become known as Genocide. Fearing that Apocalypse would kill her son who was a potential successor, Autumn took her son into hiding and never allowed the boy to meet his father. Eventually, Genocide would serve as a Horsemen to Archangel and later tried to take his father's place, but failed on both fronts. Even to his later Horsemen, Apocalypse, who never met his son, never showed a fatherly disposition, even though he considers much of mutantkind to be his offspring in one way or another.
While it may seem that Apocalypse's fathering has left a lot to be desired, his status as one of the oldest mutants has positioned him as a father figure to generations of mutants, especially those chosen as his Horsemen. Talking to Archangel before arriving at the Starlight Citadel, Apocalypse remarks that he is glad to see his Horseman in the form that was bestowed upon him, with his blue skin and metallic wings. Gifting all of his Horsemen with equivalent transformations, it is clear that Apocalypse sees his actions as essential to their growth as mutants and the next stage of evolution. As Warren notes, Apocalypse's willingness to sacrifice anything or commit any heinous action will lead his children to turn against him as the ultimate end of his sins.
As a father, it is clear that Apocalypse cares about the mutants under his care, as his recent mentorship of Rictor suggests. However, as one who has lived for thousands of years, he is also consumed with his long-term plans for the future that motivate all of his actions. After raising Rictor up, he then used him as a pivotal piece in his betrayal of the Externals.
By giving all of his power and wisdom to his children, Apocalypse also sets the path for his downfall, when his actions inevitably come to catch up with him. Ultimately, this warped devotion to his children makes Apocalypse all the more sympathetic and even more terrifying.