Another World Contractor

Read manhwa Another World Contractor / 이세계 청부사
Jung Won travels between worlds, working as a “contractor” (hitman/mercenary). After deciding to retire from his contractor work and return to normal life for the sake of his younger sibling, his brother Jung Yoon suddenly disappears into the other world. Now Jung Won must reclaim the powers he lost upon retirement and venture back to bring his brother home. Can he recover his lost abilities and rescue his sibling?!