Dorei-gaeshi no Hangyaku Maou: Saijaku Shuzoku no Akuma ga Kindan Harem wo Kizuku made

A century ago, humans defeated demons in war, and the surviving demons became slaves under the Goddess's rule. Born as a demon in this world, Liebe is reincarnated into a life of servitude after being bullied and dying in an accident. He is forced to serve as a pet-slave to a noble's daughter, bound by a contract that prevents resistance. Despite this, Liebe has the rare ability to see weaknesses in others. Using this skill, he creates a spell to temporarily nullify his contract. Determined to make the most of his demonic nature, he aims to become the ultimate demon king and lead his people.