Yandere Big Brother X Baby Sister! (NSFW)
(Smut/Taboo/Love/Incest. Read at your own risk)
This story is about a 17 year old boy called Shi and his younger sister Hana, who is 4 years old. They are really close (if you catch my drift) and Shi won't let anything come between their relationship. Shi loves his sister with all his heart and promises to always look out for her after their parents pushed them two away. They both live together alone in a small apartment which has been perfect until Shi gets more paranoid and over thinks everything because of something he heard on the news. Going crazy, Shi doesn't know what to do so he becomes even more protective of Hana...Doing things out of the thinkable.