I Write Diaries Roasting Girls Like MyGO, but the Old Bands Are Spying on Me

After transmigrating into the BanG Dream world for 18 years, meeting the old bands, and getting into the University of Tokyo, the System finally arrived. Having read diary-style stories before, Ueda Yu saw through the System's scheme: anyone with a copy of the diary could read what he wrote. Thinking he had gained the upper hand, Ueda Yu decided to make up diary entries mocking MyGO and Mujica, deliberately let the girls see them, and then change the plot through his actions. He never expected the System to trick him with wordplay for its own amusement, secretly give the old bands copies of the diary, and keep that from him. Completely unaware, Ueda Yu mocked not only MyGO and Mujica, but also the band girls he knew personally. He didn't notice the girls' gazes growing more and more unsettling. Until the day the truth came out. Watching the band girls encircle him and steadily close in, Ueda Yu finally understood that he was the prey. "System, you're seriously not human! I opened my heart to you, and you played mind games with me. You really did a number on me!" [The System was never human. Host, you're on your own.]