The Contract With Her Father's Billionaire Rival - Chapter 1. The Fire.

A young man playing games in his basement is struck by a mysterious bolt of lightning, killing him instantly. However, he wakes up in the body of a disgraced young lord, now tasked with managing a ruined, crumbling kingdom. With no experience and a tarnished reputation to overcome, his future seems bleak.Fortunately, he possessed the Omnishop System, a mysterious tool that enabled him to purchase skills and supplies as well as upgrade his existing skills using points. Rebuilding the kingdom is no easy feat, but Alexander has his sights set on more than just survival.With ambition burning in his heart, he dreams of ruling an empire, if he can survive the challenges ahead.

Fate, a gatekeeper who had been working for the castle, is beset by a few burdens.

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

Vincent Strider was a gun for hire who made a living by killing whoever it was his clients wanted dead. But during one mission, he died in a fierce gunfight. However, death was not the end for him. Vincent found himself reincarnated in another world, facing a floating interface that flickered before his eyes.[Synchronizing Host!][Military System initializing.]Vincent found out that in this system he received, he can summon soldiers, tanks, aircrafts, and even warships! This is going to be exhilarating.