The Two Of Us Against The World [Kiyone x OC/Reader]

Zero is his childhood name as well as his codename. A boy... An orphan... A Prodigy... The child was unpredictable. No. It would be better to describe him as unstable. What drives him is unknown. What he reaches for is the unknown. What he seeks... What he ventures for... What is his path? He wished to explore the world with her... but now? Does he deserve this luxury? Is it luxury? Or is it... just hell? The person he's become... The reputation he's built... What would she think? How would she react to the monster he's become? Would she still love him? He's unrelenting. He's fierce. He's inhumane. He's cold. He's cruel. He's merciless. He's ruthless. He's a killer. He's zero. But why is he zero? “They say it’s because he has zero emotions.” But if that's true... Then what's his reason to exist?