Ascendant Across Realities. - Chapter 37 - 36: Countermeasures.

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.

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

He is an undead who is devoid of all humanity, he is the one and only supreme overlord, he is a man who has severe mysophobia.

After struggling in the apocalypse for ten years, Yao Ran died and returned to the three months before everything began. She returns with hatred and thirsts for revenge, intent on making those who owe her pay with their lives.With her grandfather's inheritance, Yao Ran sold everything and frantically hoarded weapons, medicine, food, and supplies. She sharpened her sword, stockpiled up supplies, settled scores with scoundrels and villains, and repaid them with both enmity and kindness.When disaster strikes, she begins her revenge, facing a dangerous world, and is determined to outlast her previous life.