Angel of Calamity (Sephiroth reader x Highschool DxD)

Bio and Prologue

Name: Sephiroth

Birth name: Y/N L/N

Title: One Winged Angel

Age: 5,527 have the appearance of a 16 year old

Gender: Male

Weapon: Masamune

Appearance: Either this one

Prologue

5,000 years ago there was a war between the 3 fraction. Angels, Fallen Angels and Devils. Many lives were lost, many ancient beings woke up to fight. But one day on the war a devil and a fallen angel were fighting near a human village until it escalated to the point they were destroying the village, but then a female human tried to tell the devil and fallen angel to leave, only for the fallen angel threw a spear of light in the woman midsection causing her to die. That day was the biggest mistake that fallen angel could have done. That day was the birth of a monster in human skin. When the fallen angel killed that female human her lover saw it all happen. A human male saw his lover get killed right in front of him. Rage and vengeance fuel the human as he use somehow absorb his Sacred Gear, Sephiroth's Grail, and became the monster that put the Angels, Fallen Angels and devils to near extinction. The 3 factors made a temporary alliance to defeat the new threat. The fight lasted for 100 years and they haven't made any progress on defeated Sephiroth. The 4 devil kings have been killed by Sephiroth, God has been heavily wounded, the two heavenly dragons has been sealed away and everyone are losing hope on defeating Sephiroth. That until Michael had an idea to seal him away. With the help of Great Red and Ophis combine, they were able to seal Sephiroth away inside the Dimensional Gap. But before they sealed him, Sephiroth said his final chilling promise

"I. . . Will never be a memory. In time the seal will break and I WILL come back. That's a promise"

And just like that the seal took effect and turned him into a dark purple stone that emits strong dark energy