Isekai Shihai no Skill Taker

This is the story of a young boy who will one day come to be known as the "Ruler" in another world. Yuuto Konoe, a martial arts prodigy, is summoned to a foreign world where slaves are bought and sold. There, he acquires a unique skill called "Skill Taker," which allows him to steal the abilities (skills) of defeated monsters. While aiming to build a harem of 100 slaves, he begins his leisurely life in this new world.
(This work is based on the light novel "Skill Taker's World Domination: Building a Slave Harem from Scratch" by Kodansha Ranobe Bunko, adapted into a webtoon.)