I Have An Impenetrable Fortress

One day, Zhang Dongyun transmigrates with the Impenetrable Fortress System. As the Fortress Lord, he is invincible within the boundaries of the fortress, and he controls the fates of everyone inside. Nothing can harm him, and no one can destroy or damage the fortress except him. While he searches for the remaining fragments of the immortal ruins to extend the time of his invincibility, he also constantly upgrades and expands his fortress. Henceforth, the world welcomes its one supreme ruler, father of all, and everlasting God.