She Looked Down on Me, so I Took the Opportunity When She Was at Her Weakest to Become My Personal Sex Toy, My Cum Collector

When their father remarries, he has two sisters who are beautiful and cute, but the main character, who is a shy and unpopular guy, spends his days being shunned, and looked down upon by them. He spends his days masturbating to them as a hobby, while harboring black feelings for them, who treat him like trash, cocky and haughty. One day, on his way home from his part-time job, he passes by a park and sees a startling sight.