The Abandoned Key

Full summary

Y/N is the first pawn of Rias Gremory, but there's a problem. He's weak. Yes, Rias reincarnated him because she felt a lot of power inside him but no matter how many times she tries to help him draw out that power it was always failure. Y/N is a good friend to every member of the ORC so the other didn't mind if he was weak because they knew it takes time to grow strong, Y/N has some skills on using a sword and trains with Kiba much to his pleasure, Koneko always liked him and told him her true nature being a Nekoshou, Akeno always loves to tease him because of how innocent and dense Y/N truly is. Everyone, even Sona and her peerage, likes him even Gasper, who even opened up to Y/N as they spend time playing video games in his room. But a certain Red haired devil is starting to hate how weak Y/N truly is. One day Rias send Y/N to kill a stray devil alone, Y/N blinded by his trust to Rias, he left without complain, what Y/N didn't knew was that Rias sended Y/N to kill a S-Class Stay Devil. Koneko's older sister, Kuroka.

As he arrives to an abandoned Warehouse he found a heavily injured Black haired girl wearing a kimono, she has black colored cat ears and two black color cat tails. Kuroka glare at the intruder with killer intents, Y/N approaches her and started to heal her wounds. Kuroka was shock seeing someone helping her she asked on why he's helping her he only responded that he wants to defeat her at her full power, he also said that he didn't like the idea of killing a defenseless woman, this shocked her even more by the amount of kindness he displayed on her. Once he finished healing her he took some distance away from her to start the fight. After there fight, Y/N was on the ground full of bruises and injuries, Kuroka helped him up only for the both them to be blasted away. He struggle to see who his attacker was only to see him king. Rias Gremory stared at him in disgust as she approached him and shot an orb of destruction point blank on his chest making a huge hole where his heart and stomach was. Y/N, somehow still alive stares at Rias with his now dull E/C. She only responded with

Rias: Sorry Y/N, but I have no use for weaklings on my Peerage

That's when he found out her plan. She planned for him to die from fighting Kuroka but since that didn't work she killed him herself. Kuroka extremely angry stared to fight Rias only for her to smirk as the rest of her peerage arrive and witnessed a dying Y/N. Before Kuroka could explain anything Rias placed the blame on Kuroka making all of them to fight her and Koneko to hate her even more. Kuroka was heartbroken when she saw the amount of hate on Koneko's eyes that she teleported out of there crying. Rias removed her pawn piece from Y/N and left. As Y/N was slowly dying he closed his eyes to embrace death.

Only to opened them up full of rage as his wound magically healed and a strange sword in form of a key to appear in his hands. His body completely covered in both light and dark energy as it slowly died out. His sudden awakening drained him of his energy as He fell unconscious. He later wakes up but there's was a problem.

He's in another world