Maybe a Fake Gintama - Chapter 3: Kawaki, Gintoki, Takasugi and Katsura

Karsha, a general in the United States Army, was a loving father and husband who was accused of killing his wife and two children. As a result, he was sentenced to death. However, his life took a turn when a sinister being transmigrated his soul to a world of cultivation. He awakened as a slave and slowly rose through the ranks thanks to a strange system with its own agenda. He began walking the path of cultivation and immortality, which will soon drive him into a conspiracy so grand that his understanding of who he was, who he is, and who he is to become will be put into question.

An ordinary person who has passed through the Marvel World to gain the phagocyte ability and began to devour superpowers, and became the king of Marvel!

There are many female lords. The protagonist has gradually become the king of the Marvel world from ordinary people. The initial ability is the physique that changes through traversing. It can devour and stabilises without any side effects. The system is only an aid, you can also cross the plane!

- Description from Novelupdates

Apollo Kaiser, a boy who bore the unlucky fate of being unable to grow strong, was condemned by his family.

Discarded by his mother and abused by others, Apollo gives in to his rage.

However, this action results in his death. Many would believe it to be the end, but Apollo's death was a required catalyst.

The Demon Monarch System finds its heir and attaches to his soul, bringing him to a new world where he starts his journey to supremacy.

This difficult journey rife with conflict, conquest, and brutality shall serve as Apollo's temperance.

Watch as the heir of the Demon Monarch rises above all, conquers Sin, subjugates unthinkable enemies, and even brings about the destruction of worlds!

The rise of the next Demon Monarch begins...