[どろっぷす!] 地味義妹⇒黒ギャル痴女化！？ ～引きこもりから淫乱へ大改造～ モザイクコミック総集編

Finally, he took her out, and they went to stylist. On their way back, people saw them having sex and joined. He hand her over so they can continue making her more into a slutty black gyaru. In the end, he got afraid of seeing what she had become. Ai sent him her sex video, and he finally decide, if she became like this because of him, then it's also him who must bring her back. Only, she's already too far gone. The MC became hikikomori from the despair. Ai visited him, and told him she's pregnant. She wants her brother to take care of the baby so she can keep getting fucked, and he got no right to refuse as he also came inside her before. She told him, she will keep becoming sluttier as what her brother wants her to.

...that's terrible story. Ai is the MC's stepsister who became hikikomori after becoming bullying victim. He took care of her, and she became too dependent on him. Of course, she protested when he plans on moving out of the house. So, he remembered an interview where an ex-hikikomori now became a slutty gyaru because her boyfriend likes that kind of girl. He start by telling her he loves her, and then asks her to change herself for him. She pierced her tongue, learn make up, and start to make sex recording.