My Story of Subjugating and Conquering Another World!

The Protagonist together with his whole school was transported to another world. When they were evaluated the protagonist was deemed as a weak character as he has only one skill. At their first expedition they were ambushed ,the Hero, which the student council president, used her skill [The Ruler] to control the protagonist together with his other classmates to act as a bait. In the midst, of the battle the protagonist was fatally wounded and fell into a cliff. While he is falling he vows that he will get his vengeance if given a choice, to the people that brought him to that point, suddenly a voice called out to him and offered him power. He is fused together with the voice that he heard and gained the skill [Absolute Obedience], a skill that has the ability to control a human or a demon for eternity. With that power he will have his vengeance and conquer the world.