Apocalypse: Apparently, I Can See Zombies - Chapter 65- The Single Most Important Boy In The World

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

As an international mercenary, Feng Luo entered a technologically advanced parallel world during a mission.

After living several years in the new world, an online sci-fi game called War became popular across the entire Star Federation.

Desert Eagles, Barrett, AK-47, Apache, RPG… One after another, familiar gears awakened his memories of the past!

Terminator, Zerg, Resident Evil, the Force,… The missions that appeared after a system update made him even more suspicious and shocked! As such, Feng Luo entered War and became a sniper.

After the Catastrophe, every rule in the world was rewritten.

Six years ago, he disappeared silently! After six years, he becomes the unparalleled "God of War" and returns with glory, only to find that he has a daughter whom he never knew of. Looking at his wife and his daughter, he says, "In this lifetime, I'll bring you the greatest honor and glory!”