Protagonist's Evil System: My Girlfriend Turned Into A Dragon

Lucas, a regular student, receives a surprising date invitation from the most beautiful girl in school. However, their date takes an unexpected turn when Lucas is suddenly transported to another world. In this new world, he gains a rebellious system and some mysterious pills as rewards, unleashing a hidden darkness within him. Lucas must now learn to control this power, which originates from the previous protagonist of the world. The system offers to grant one wish if Lucas can win the game he has been thrown into. This motivates him to do whatever it takes to win and help his sister regain her health. To succeed, he must follow the system's rules and form a team with a human, an elf, and a "partner." Collecting avatars and mastering their abilities, wielding given weapons, and ultimately defeating the black wizard in a tournament are necessary for Lucas to emerge victorious. With time running out, Lucas faces a chaotic situation, starting with his date transforming into a dragon.