Lord of the Time: I Can Reincarnate Infinitely - Chapter 5 - - Steely Resolve

Crossing into the world of Naruto, and acquiring the One Piece system, with all the powers of the world of One Piece, swordsmanship, devil fruit, domineering.

-Do you think that your fire is very powerful? I have the burning fruit.

-Do you think that your thunder is very powerful? I have a thundering fruit.

-Do you think that your otter is very powerful? I have the frozen fruit.

-Did you said you want to die? Don’t worry, I also have a nickname: Death Doctor.

- Description from Novelupdates

The strongest Demon Lord dies, and reincarnates as a human. Not only that, he because of various incidents turns into the hero’s best friend.

Follow his journey as he tries to help the hero escape his fate, and on the sideline to conquer the continent while he’s at it.

Once all people received Souls and incredible powers. Some were lucky enough to obtain the Soul of an ancient and powerful creature, but fate was not favorable to all.

The world began to change, and creatures evolved. But, it was not the beginning of a new era. It was the end. A couple of months later, a dark mist appeared and destroyed the world. It was a dictate of destiny from which no one could escape.

Wain Norheim was the world's best assassin and the only one who didn't get a soul. However, he was destined to gain the power to confront fate.

Escaping through a portal into another world, he unknowingly began the apocalypse. Even the world failed to expel him.

Gripes have their origins and debts have their creditors. We haven’t crossed each other in days past or present, nor formed any grudges. I am but duty-bound to carry this out, so apologies in advance!

In his past life, Yang Chen was a gentle person who was oppressed for his whole life.

Now that he’s reborn, he chose to become an executioner and severs ties and grudges with his executioner’s blade, killing all that climb onto the Immortal Executioner’s Platform!

Heads will roll! Humans’ in the human realm, demons’ in the demon realm, devils’ in the devil realm and immortals’ in the immortal realm!