I'm Just a Side Character in a Dating Simulation

On that day, a girl wearing strawberry underwear fell from the sky. “This place is actually set in a GAL Game world!” And not only was I, who was raised in a prosperous family and was outstanding in everything not the main character, but I was also instead this world’s villainous and antagonistic Eldest Young Master?! I had decided. I shall forge an alliance with the strawberry girl, and together we shall wage war upon the main character for the one true love! I don’t care for his main character’s aura or his Yasashii Strategy. I shall open up a grand path to becoming the main character! I refuse to be a side character in a dating sim!"

(Source: Bilibili Comics)