Centuries ago, a man of the name of Mordekaiser terrorized the world of Runeterra with an iron grasp. He was eventually rebelled by neighbor towns that riled together to defeat him. Years passed until he was resurrected by his most loyal pupils. Once again Mordekaiser started a conquest but instead of commanding as a man, he commanded as an Iron Revenant. He was taken down by the townspeople again, but to some he was recognized as the one to unify the land. These people banded together to once again bring their great leader back into this world, known as Nightfall’s Eve.
Phobos was born into this life centuries after Mordekaiser’s second reign. He was destined, with all the others in the cult, to become a ruthless, yet skillful soldier for Mordekaiser's inevitable conquest.
Living in the outskirts of Noxus with his older sister, Phobos and the rest of Nightfall’s Eve live in secrecy, pretending to be Noxian nationalists. He and other children under the organization, when of age, are immediately enlisted into the Noxian Youth. Aretha had already proved to be a more than capable warrior, unlike Phobos. Even though their age is separated by a few years, Phobos is nowhere near as receptive or bloodthirsty as his sister. Easily frightened, and poor hand eye coordination, has kept him from being able to grasp things as quickly as others. While in the barracks, Aretha’s attitude changes from a cold blooded warrior, to a caring and compassionate sister, but only to Phobos. She wants her brother to succeed so that they both can be of use in their next life under their godlike leader.
As the years pass, Aretha continues to rise in the ranks, gaining more and more prestige with each passing day, while Phobos only rises in stature. Phobos is fearful that his sister will eventually leave him behind, so he trains not in weapons, which he has shown he has no prowess in, but in body. Becoming a behemoth of a person, so that he can try to use his brute strength to fight.
As Phobos trains to be of use to his sister, instead of of the sect, Aretha has become of age in the Noxian ranks to leave the city with her own battalion to start her own Noxian conquest. But this is what Nightfall’s Eve wanted, for a single soldier, to rise high through the ranks, and lead a squad of battle hardened militants, to search for the skull of Mordekaiser. Aretha leaves Noxus with her hand picked group, which didn’t include Phobos, since he didn’t have a high enough rank, nor battle experience to help on her agenda.
Phobos’ greatest fear had finally happened, his devoted sister had left him. Days after her departure from the capital, Phobos collects his items, and left the city without a trace, to follow his sister. Unknowingly to him, the Noxian elite had sent a squad to follow Phobos, knowing that he would follow his sister. The elites knew about both Aretha and her squad’s ties to Nightfall’s Eve, and also sent a group of assassins to execute the rest of the group in the outskirts.
Phobos follow’s Aretha down the coast of Runeterra, stopping at every port where Aretha could have stopped, asking questions to all the locals. As he travels further and further his fear of Aretha leaving turns to anger to why she could have done something like this to him. Weeks pass before he even sees the company that Aretha left with, at a port near Piltover, but the Noxian elites are just as close to Aretha as Phobos is.
As night creeps onto Phobos he sleeps within visual distance of his sister and her company. He is quickly awakened to battle cries, and as his eyes adjust to the night setting he sees two Noxian battalions attacking each other with every inch of power that they have. Phobos cowers behind the hill he slept behind and gazes upon the destruction of the two opposing forces. Only after a short period of time, both sides were completely destroyed, except one person. Aretha. Phobos leaps to his feet and rushes to embrace his sister, only to see her eyes widen with horror as another Noxian soldier rushes behind Phobos. Aretha rushes to Phobos’ aid only to intercept the attack meant for him. Phobos can only stand in fear as the Noxian soldier plunges his blade into Aretha’s chest, until the rage from deep inside causes him to pick up Aretha’s sword and plunge it into the man’s helmet. After the soldiers quick death Phobos can’t contain his rage and keeps hacking away with hatred until there is nothing left of the body
Phobos turns to his sister who lays dying coughing blood on the bloodstained battlefield. As she lays there dying, she can only mouth one thing, “ We found the location of the skull…” before her body slowly becomes void of life. Phobos can only sit there in disbelief to realize that he is the reason that his sister is dead. That no matter what he did he was dead, if he left or stayed, but leaving only made more bloodshed. But he remembers her parting words, that she found the skull. He gets to his feat with the hatred of his sister turning into hatred towards Noxus. He will get the skull. He will resurrect Mordekaiser. He will destroy Noxus. He will avenge his sister.
He finds the map among his sister's belongings in the camp, and the armor and weapon that would be given to Mordekaiser when he revives. Filled with a new passion to bring about his unholy god, just as he and his sister were destined to do. His devotion to Mordekaiser had now begun. He traveled south with both the armor and his sisters decaying body, as headed for the Blessed Isles. When Phobos arrived at the isles, and found the crypt that held the skull of Mordekaiser. After burying his sister next to the crypt, he said a blessing to Mordekaiser, and attempted to open the crypt until the ground started to tremble.
The isles turn to a deadly gray, killing everything in its path. Phobos’ eyes widens as he realizes what is happen, but before he could flee in terror, the curse reaches him. Phobos just stares at his lifeless body, as he just floats there in disbelief, until the mixture of fear and anger for failing his sister is too great his soul erupts into fiery purple flames.
Phobos’ awakens to the sight of armoured legs, and the clanking of metal as he stands up. He sees that the crypt that he wanted to open about to crumble. He picks up the massive halberd, that he can now lift with ease and slams it as hard as he can shattering the stone in that instant, except the skull lying in the center of the rubble. He must complete Aretha’s quest. His quest. As he picked up the skull, and carried it to a makeshift altar liches swarmed him, ready to attack.
Phobos barks at them, that he is there to resurrect the great leader and places the skull on the slab of rock, as the liches place the rest of the bones on it. He helps the liches set up the ritual, and beings the incantation with them. Over the slab of rock a malicious being begins to take form, until after a thunderous boom, Mordekaiser appeared in front of them.
One of the liches hands Mordekaiser his Mace, as he turns to Phobos and asks, “Who are you?” Phobos responds quickly with rage in his voice, that he resided in his old fortress with a group that wished to resurrect him. And all Phobos wished to do now was to crush all that opposed Mordekaiser. Mordekaiser bellowed a rough laugh, until he responded with, “And you shall, but first tell me more about my old fortress.”