Note: Not a Smut. 
High school student Fushimi Makoto is a time traveler. He not only traveled to the world of anime, but also fell into a time loop.
He spent countless years on the same day. He tried to use the time loop to capture all the two-dimensional beautiful girls, Yukinoshita Yukino, Kasumigaoka Utaha, and the five Nakano sisters.
When he began to feel irritated and numb, the time loop suddenly ended, and the system came along.
[Intern system 4399 reports, I finally found you, my host. ]
[Time problem detected, damn, how did the host spend decades in this world? ]
[System tasks were forced to update, and now the internship system can't graduate, sad. ]
Fushimi Makoto: "Don't panic, I have a plan. Anyway, it's already like this, I'll help you complete the internship, and you'll help me get the reward, it's a win-win."
System: Please elaborate.
[System task has been released: It has been detected that the host already knows Yukinoshita Yukino. Since you have lived decades longer than others, please become her favorite elder. ]
Makoto Fushimi: "Simple, I'll deal with Mrs. Yukinoshita."
System:?

Character's Images (SPOILER ALERT)