Nocturne has been now around for decades, centuries... even millenniums and he has been trying to use the World Runes in his benefit to destroy Runeterra, and it all started because the nightmare of a little boy named Ryze.
Ryze was just a kid when he started to have horrid nightmares, but he couldn’t take rid of them, so when he was searching for help, the priests of the Temple of the West offered him help in exchange of becoming an apprentice magician. He accepted and as he started to become an adult, the nightmares where less and less frequents until they finally disappeared... until Ryze’s initiation day. He was finally going to become in a formal apprentice of magician, but something terrible happened during the initiation ritual - which implied a huge flow of energy going towards the subject - and Ryze fell asleep. It wasn’t a normal initiation ritual, after the initiation ritual you became a completely different person and your body would be covered of runes.
-The subconscious of Ryze stopped transferring the energy to himself, but it was being transferred somewhere else, a place nobody knew just yet: Nocturne’s world. Nocturne was the nightmare of Ryze when he was just a child until the rising power of Nocturne was stifled by the Order of the Runes, but he never died, he was waiting the precise moment to rise up stronger than ever, and the moment came during Ryze’s initiation ritual. The flow of energy that Nocturne absorbed was so obscene that he was able to open a portal from his reality to Runeterra, a glitch, a huge mistake that triggered the World Runes war and almost became Runeterra’s destruction-.
Immediately, Nocturne rose from Ryze’s chest and he darkened Runeterra. Ryze woke up, but he could see nothing nor move, but during what seemed an eternity he heard how every single member of the Order of the Runes fell apart against the new acquired power of Nocturne. After just three eternal seconds Ryze was able to move, and when he opened his eyes, he was able to see the Initiation Chamber: and the destruction that Nocturne took three seconds to create:
the floor was flooded with blood and every body of the Order members where completely massacred with infinite cuts that suppurated pus and liquid darkness wherever Nocturne touched the flesh of the bodies around Ryze. After searching any signs of someone alive he found that the High Priest of the Order was trying to say something. Desperately, Ryze ran where the High Priest was. The High Priest was chocking with his own blood but Ryze recognized almost everything that the Priest said: “Defeat that monster, now you own my (intelligible) runes”.
Immediately after, the High Priest died, and Ryze started to cry disconsolately not knowing what to do. Ryze stayed several hours in the chamber until he wasn’t able to cry anymore, he stood up and realized that he was naked and that his skin was blue and it was covered of runes from head to toe. Slowly, he walked to his accommodation and started to wonder what was the missing word of what the High Priest said to him: “now you own my _____ runes”. Ryze never saw that the body of the High Priest was blue, or even covered with runes, so it wasn’t it, he neither saw that the High Priestess needed anything to cast his runic spells.
Exasperated and very tired, Ryze decided he needed to sleep and clarify his mind before taking action about the massive murder of the Order, and that was what Ryze did. The next day he did nothing else than staring at the ceiling, as well as the next day of that one, and the next of it until something happened that made him realize the world was in danger: the world blacked out for exactly three seconds: he couldn’t see nor move during that time, and he realized that the blackout in the Initiation Chamber was just like this one, and that Nocturne was the one creating them.
For some reason, Ryze’s mind was illuminated by that event and as soon as he could move, he ran faster than ever to the High Priest’s accommodation. Ryze found that the door was locked and that there was a safe-spell on it. He pushed, hitted and kicked the door as hard as he could, but it was just not enough. After a deep breath, he tried something that he had never done: summon a rune to destroy the door and enter to the Priest’s accommodation -His initiation ritual brought Nocturne to our world, but thanks to that, Ryze now was also able to cast spells-. With a blueish glow the door exploded like if it was made of glass and not of the strongest oak existent in Runeterra. After the accommodation was clear of dust, Ryze entered to it and it looked like any other accommodation -a bed, a bureau, a window, a small restroom and a small desk to read and write- except for what looked like a pedestal and a book on it. Ryze walked carefully to where the book was and after watching it for a second, he opened it and... nothing happened, it was a simple book. After looking at all pages, he realized that the book had no signals of having anything written. Disappointed, Ryze throws the book to the floor with no apparent damages except for a single page that slides slowly out of the book. Ryze hurries to take it and surprisingly there are only two words written in it: World Runes.
Whit that in mind, Ryze steps forward to the window and looking to the horizon, book in hand he makes the promise that he will not rest until Runeterra is free from Nocturne’s evil influence and with that, he starts his endless and eternal duty of recollecting all the World Runes to send Nocturne to his own dimension… forever.