Setsuna in the Loop

His beloved younger sister committed suicide. The cause was horrific bullying by seven members of the student council. The protagonist, Setsuna, swears revenge against the student council and puts his murder plan into action. However, no matter how many times he kills the student council members, he keeps getting sent back to a timeline where they are still alive. It seemed as though his revenge would remain unfulfilled due to the time loops, but Setsuna realizes a single possibility: would the time loops occur if a third party instigated the murders and carried out the revenge? Use every trick in the book to frame someone for incitement to murder! The time-loop revenge drama begins!