家族を囚われ、魔王討伐パーティーに入れられた盗賊キース。
彼の活躍もあり無事に魔王を倒したが、
キースを快く思わない国王や勇者たちに裏切られ、殺されかけてしまう。
命からがら逃げのびたキースの頭には気づけば禍々しい角が生え、他者のスキルやステータスなど全てを盗める破壊と暴力の化身❝怪盗魔王❞に変身していた!!
前魔王の配下【四天王】と魔物を従え、裏切った人間どもに鉄槌を下す!
Keith, a thief, has his family taken prisoner and is forced into a party to defeat the Demon King.Thanks to his efforts, he manages to defeat the Demon King, buthe is betrayed and nearly killed by the King and heroes, who are not happy with Keith.Keith barely escapes with his life, but before he knows it, sinister horns have grown from his head and he has transformed into the “Demon Thief King,” an incarnation of destruction and violence, able to steal everything from others, including their skills and stats!!With the former Demon King’s subordinates, the Four Heavenly Kings, and monsters under his command, he will bring down the hammer on the humans who betrayed him!
