Adventurer of Many Professions - Chapter 9: Interrogation!

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

After seeking pleasure in the nightclub and a night of romance, he discovered there’s a seed in his stomach;

There are countless parallel worlds beyond what we know. The people who first discovered this secret named it “Yan Fu”. Each world is a different fruit on a tree, and the person who shuttles through different fruits is called “Yanfu Walker”. Yanfu Walker is given different Heritage and trained to complete Yan Fu missions in exchange for rewards.In modern society, the Martial Arts sects have declined one after another, and martial arts prodigy Li Yan suffers from leukemia, making it difficult to survive by opening an audio and video store. One day, a person named MO appeared and took him into the Yan Fu world under the pretext of being able to cure a terminal illness. So “Hejian Skinny Tiger” Li Yan resolutely stepped into the world of Yan Fu, awakened the inheritance of Gu Huo Bird, and embarked on the path of survival in a different world. The truth of the world, Yan Fu’s goals, the secrets of the walking organization, and the ambitions of the rebel organization are far more than that…

I got transmigrated into a game I’ve never seen before.

I thought it was a top-notch RPG and spent 30 years on it.

I retired as a war hero and planned to spend my remaining time leisurely.

But it turns out, it was an academy story?