Forced to Sell Myself to the Female Lead After Killing the Male Lead - Chapter 12 - :

What do you do when your brother dies because of some entitled assholes? You go undercover.My real name? Clare. But at school, I’m Clause—just another guy blending in. Disguised. Watching. Yes, a boy. No, it's not an all-boys school—I'm just deep undercover, hunting down the bastard responsible for my brother’s suicide. Nobody—and I mean nobody—messes with my precious brother and gets away with it. They better pray I never find them, because when I do? Death will be a mercy, and trust me—I don’t do mercy.And as for the egotistical Alpha and the narcissistic Vampire Prince? They can go fuck themselves. I don’t do mates, I don’t do claiming, and I sure as hell don’t do them.

Collapsed without warning, and upon awakening, he found himself back in his childhood.He thought it was a blessing from above, but unexpectedly, tumultuous changes ensued, shrouded in mystery...

[Ding! Congratulations to the host for obtaining the 9-Tailed Heavenly Demon Fox Bloodline.]The Celestial Fox Deity: “Little Ancestor, our geniuses are struggling to advance their bloodlines. Could you spare just a small drop of your diluted blood?”…Cain wakes up only to find himself transmigrated into a novel that he had read a few years before his death.In this new fantasy realm where the strong are respected and the weak are trampled, Cain awakens his “Unique SSS-Ranked Primordial Beast Master Talent” before an error happens and merged with “Extra’s Harem Gacha System” which can help him become stronger by having sex with powerful women, including those summoned from the system’s Summon Pool.[Ding! You have shared an intimate moment with the Goddess of Light][Ding! You have received …% of her stats attributes][Ding! You have increased her stats attributes by …%]After merging his talent with the system, he can also contract and evolve powerful beasts, instantly upgrading their ranks using Evolution Points.With the ability to convert money into Evolution Points, Cain decides to build his own force, amass wealth, and take full advantage of the system’s potential to rise above all.[Ding! Do you want to refine the Ice Dragon’s Evolution Pill?][Ding! Do you want to refine the medicine liquid of God's rank?][Ding! Do you want to refine the Godbreaker sword of the God’s rank?]…

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.