This story is based upon my Zemyx/Dexion head canon. At first this story is going to seem kind of creepy and perverted however it shows how Zexion got to be the way he is and how he came to meet Demyx. It starts off before the Organization XIII members become Nobodies. Ienzo was abandoned by his parents and was left in the gardens of Radiant Garden. He is found by Even who will use him for his scientific experiments and much more. Most of the detail is written in the head canon below, however you will find out more as the fanfiction goes on. I hope you enjoy and please leave me constructive criticism. Thank you.
We all knew about Vexen. When he had his heart he was known as Even, he was a mad scientist and a paedophile, he was highly protective of Ienzo all for this reason though. Ever since Ienzo was found by Even, Even took him in to the castle at Radiant Garden. Since that day Even used Ienzo. Ienzo was used for Even's scientific experiment, he was in heaps amount of pain each and every day, and on top of that he was also sexually abused by Even.
Some days Even escaped from the castle. He didn't want to be there and all he could think about was death, but one day when he was out of the castle he heard something. The most blissful sound he had ever heard. It was a guy playing a Sitar. This guy was Demyx and he was a homeless guy. He would be in the streets of Radiant Garden each and every day playing his Sitar hoping that people would give him money. Not one person did. On this specific day when Ienzo found Demyx, he sat on the bench across from Demyx listening to the blissful music he was playing.
While listening all the bad things went from his head, it was like he was in a completely different world, just a world of him and Demyx, during that moment Demyx stopped playing his Sitar and walked over to introduce himself to Ienzo. He could see Ienzo was pained. After that day Ienzo would attempt to escape the castle just so he could see Demyx [ONLY USING DEMYX CAUSE NO ONE KNOWS HIS 'SOMEBODY' NAME]. They would get to know each other more and eventually they fell in love. Ienzo told Demyx stories each day or what Even would do to him and Demyx would be understanding and promised Ienzo that one day he would get him out of there.
One day the darkness came to Radiant Garden and while Ienzo and Demyx were together, the darkness took their hearts and that's how they got to be in the organization together, as Demyx and Zexion. They would still be together and when they were alone we could see their happy sides and what they were truly like. When Zexion eventually got the power to give people illusions/hallucinations he would cast them upon Vexen to give Vexen the torture he gave Zexion when he was Ienzo.