Omae wo Onii-chan ni Shite Yarouka!? - Volume 3, 15th of May, Wednesday.

I was reincarnated into another world, and I’ve brought the Horadric Cube from Diablo II with me.
Being a knight is cool and all, but being a wizard is pretty neat as well.
So, which one will it be?

- Description from Novelupdates

This is the story of a crazy lich who possesses an internal game system and brings catastrophe to the entire world.

Every little girl's fantasy is to live a wonderful life full of riches and luxuries. This was the future she imagined, and she was willing to go to any length to obtain it.She was spoiled, pampered, and doted on by her family, and she was proud of herself. She knew she deserved the best, and she went for it. This, however, is where the nightmare began.Wanting to leave the clutches of poverty wasn't as simple as she believed, given the things she had to give up, the humiliation she had to endure, and the numerous things she had to lose. It was not worthwhile.When she thought she had it all, she was slapped in the face with the cold, hard truth: she was only a SUBSTITUTE.And when two of her closest companions turned on her and betrayed her, she was shoved aside and got humiliated by people she used to know.With nothing and no one to lean on, she was forced to make decisions. Decisions that gradually resulted in something breathtakingly amazing.[DING! SIGN IN! THE HOST HAS BEEN REWARDED WITH ******]

After being imprisoned in the basement by her mother for ten years, she ended her cruel and tragic life in death when they forced her to hand over the key to the hidden treasure. Getting reborn in her teenage years, she woke up in the bed of that terrible and powerful man. This time, she must take revenge on her enemy, and now she must live.