Our Turning of Fate: Karmagisa (Yaoi/Smut)

*WARNING* This story contains boy x boy, smut, inappropriate language, and violence.
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Description:
Imagine if Assassination Classroom took place in high school.
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Nagisa couldn't control his assassinator drive when it came to intimacy with Karma. His breath fell short as he felt Karma's tongue. The blue male's predator instinct was kicking in, his head screaming and pounding loudly. This wasn't love, just lust. The blunette wanted to yell, but he couldn't. "...I want to use and be used by you Karma... fight me and only me...beg for me...." Nagisa's consciousness said. Who's voice was that again? This wasn't love...right? Nagisa wanted two things and two things alone. One, to ravish Karma all for himself regardless of the consequences, and two, to love deeply and truly.
Nagisa's head pushed him over the edge, his assassination instinct was winning. Karma's voice was dimming, his red seeping into Nagisa's vision like blood.
The last thing Nagisa remembered was Karma's faded expression, lust, and the taunting killer drive like knives ripping through his brain until it all went white... and faded away.
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Nagisa and Karma's infatuation with each other would deepen... but what would happen if their relationship decides to take a route further to lengths neither are ready for? Awakening a true monster within themselves... As both males become deeper invested, Karma begins to have issues understanding the darker side of the bluenette, developing a greater sense of fear and lust. Nagisa finds himself alone and distraught. Only memories would keep them together, and the hidden "stranger" from within Nagisa's dark side would alter their relationship forever. Only each other could bring them together, and only each other could rip them apart. Will Karma and Nagisa figure it out before theres nothing left?