The reader was born from Lady Phenex, but resisted Corruption while in the womb, corruption is what allows a human soul that reincarnated in to a baby inside a devil to become a devil, evil pieces do the same thing to reincarnated devils, so he was born human, and could not be turned with the use of Evil Pieces, so Lady Phenex was forced to give him up, leaving him in a French orphanage, unaware that he was mentally 18, the age he had died in his previous life which he remembered, as well as remember his only interaction with his mother, fathers, and the insults his older 'brother' Rizer threw at him. He had inherited the Pheonix fire his birth family was known for, as well as the extreme healing and Pheonix tears, but had learnt of them on his own. He had soon learnt about the supernatural world at a young age, through encounters with stray Vampires who tried to suck his blood, and the protective Gargoyles that purched themselves on the orphanage. He soon met a stray devil who had abandoned her master so she would no longer be molested by him, who told him about the supernatural world, Devils, Fallen Angels, Yokai, all that remained hidden to the human world, and eventually the Phenex family, as well as the arranged marriage between Rizer Phenex and Rias gremory, which he was against, especially when it was publicly aware that Rias was against the marriage. He had also learned of the addition of Ravel Phenex to his biological family. Thankfully the location of Rias territory was publicly aware as well when the reader was finally aloud to leave the orphanage.  The reader doesnt let anyone know about his heritage until after the Rizer arc, when the Phenex family figures it out when the reader acts as a Proxy Knight during the Rating game and beats Rizer alongside Issei while both are engulfed in blue fire in the shape of a Pheonix.

The reader had also learnt of the Evil piece system, and wished to create a different version of the system, that wouldn't change the species of those used to Devil, as well as wouldn't require multiple pieces to reincarnate. He was able to, and called them Chaos Pieces. He had added a Gargoyle from his Orphanage named Angela (Rook), a vampire who didnt wish to drink human blood greedily named Laura(Knight), as well as the Stray devil he had befriended named Yukari who was actually a rare human Yuki onna hybrid(Queen).

Preferred Peerage members added later
Mittelt(4 pawns)(scenario: the reader is at the Church during the Asia rescue and before Rias destroys Mittelt, Kalawarner, and Dohnaseek, he asks if they would prefer to be part of his peerage, so they would not be killed,  Dohnaseek refuses, allowing the reader to signal Rias to kill him, after which both Mittelt and kalawarner agree to the proposal)

Kalawarner(knight)

Aika (2 pawns) Murayama (1 pawn) and Katase (1 pawn). (scenario: she, Murayama, and Katase are nearly kidnapped by a Stray devil resembling a wasp, but are saved by the reader, and he offers them spots on his peerage after explaining everything, too which Aika automatically says yes, while the other two hesitantly agree)(also turns out all three have sacred gears, Aika's being Tri punisher, a whip with three blades, each having elemental power for Fire, electric, and ice, Murayama's being Blade Blacksmith: Katana, and Katase with Blade Blacksmith: katana as well)

Also, If you choose to do this please message me, I'd like to know so i can read it as well.