Yu Ishigami is the series' semi-protagonist in Kaguya-sama wa Kokurasetai or Kaguya Sama: Love Is War. He is a second-year Shuchi'in Academy high school student, a former member of the Cheer Club, and the current treasurer of the high school Student Council. Ishigami is a reserved and somewhat depressed student who rarely attends student council meetings, preferring to complete most of his work at home. He usually spends the majority of his time alone playing video games.
Ishigami has a bleak and cynical outlook on life, frequently going on long rants against youth. Ishigami can be quite awkward at times, saying things that make others think he's a creep. He is also quite snarky and is frequently the one to make sarcastic remarks about the situations he finds himself in.
Despite his negative attitude, Ishigami is a kind-hearted guy who is willing to help others in need, even if it means sacrificing his own pride. Since Kaguya Sama: Love Is War is a rom-com, let’s see who Yu Ishigami’s love interest is.
Chika Fujiwara is a student council member as well. The two have a little tense relationship because they constantly point out each other's flaws. Chika often refers to him as creepy, and Ishigami often catches her cheating at games. Ishigami is frequently the only one who can balance Chika's more chaotic aspects, while Chika enjoys teasing him whenever she gets the chance.
Later, it is revealed that the two have a fondness for each other. Chika is sympathetic to his situation and Ishigami admits her genius capabilities. As friends, the two are shown to care for each other.
Miko and Ishigami have been classmates since middle school. Miko was a member of the Discipline Committee, and Ishigami was a frequent rule breaker. They don't seem to get along. Nonetheless, their beliefs lead Ishigami and Iino to care for one another without seeking recognition.
Miko was able to overcome her stage fright after Ishigami changed the Presidential Debate from a speech to a debate. Iino, on the other hand, was one of the people who protested the punishment he received from his middle school, which eventually led to his enrollment in Shuchi'in Academy. She was also the first person to comfort him after he failed to finish first in the relay race.
In the manga, their relationship goes through a lot of ups and downs. However, there are indications of Miko being into Ishigami romantically. At the end of chapter 230, it is implied that Ishigami may have some romantic attraction to Miko.