In Another World I Become a Healer With Purple Hair - Chapter 26

Once upon a time in a modern city, a man died and was reincarnated into a body and a new mythical world.

This world holding many secrets, and wonderous things, but he possessed something that was highly regarded in terms of importance and usability: SPEED.

Join Noah on his quest to acquire great power, meet new people; while also discovering the many mysterious features of this new world he'll eventually learn to call his home.

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

I finally managed to kill the demon lord.