Unstoppable Martial Arts: Starting from Fist Technique Deduction - Chapter 61 - 52: Cultivation Technique Realm

2029 was supposed to be the year humanity moved forward.Instead, a failed military experiment tore open a gate to another dimension unleashing creatures that could shatter mountains with a single strike.From the wreckage, a new era began. Technology forged from energy crystals found beyond the gate and soldiers wielding beast infusions fuels humanity’s last defenses.Soldiers, mercenaries, and the desperate are sent to hunt the beasts... and one day, to face the terror that waits Beyond the Crimson Gate.But every step closer to the gate brings one truth into focus. What waits on the other side may not be killable.

Crossing to One Piece world, he became Roger’s younger brother.

Unexpectedly, Gol-D-Roger who was in his fifties had a teenage brother. But he was so weak.

Fortunately, at the age of sixteen, he actually found himself with a possession soul system.

He had attached to the master IP man, also to the White Phoenix and to Ge Nie with his strong ability of the Hundred Step Flying Sword.

If you think that he can only Purchase these? Then you’re wrong!

Pain, Itachi, Ichigo Kurosaki, as long as there is money, any soul can be Purchased.

- Description from Novelupdates

Huang Dan’s pain nerve is innately different from the ordinary people. A little tore in his skin can cause him to sweat all over his body painfully to the point of him unable to make a word out.

Somehow, he began to cross world, following Mr. System to do the tasks…

In the first world, Huang Dan realizes what it means to die painfully and to live to die again.

TL’s summary:
MC suddenly transmigrated and is bind to a system, requiring him to solve mysteries. Born with a higher degree of pain sensitivity, he met different people in the different worlds and learns what kind of emotion smiling is.

- Description from Novelupdates

This book is about baby-making.