Kai Shimada (島田 快 Shimada Kai?) is a student of Byakudan Senior High School's classroom 2-4, a character introduced in Corpse Party (PC), and a victim of Heavenly Host Elementary School.

Kai is a red-haired high school student who stands out in the same class as Yuuya Kizami. He is a model for a popular men's magazine, known as Men's Buckle. In contrast to the quiet and behaving Yuuya, Kai is loud, foul-mouthed, and rude, often going around intimidating his fellow classmates and committing acts of vandalism; however, he's also popular among girls for his looks. He is rather selfish, shown to be willing to abandon his friends to save his own life without a second thought. He is a notorious womanizer, and it is rumored that he has as many as ten simultaneous girlfriends.

Kai is also incredibly arrogant, frequently boasting about his characteristics, and describing himself as "Mr. Perfect," and a "real renaissance man." Fitting with this, he can also act rather eccentric, and often exaggerates what he does and says, dubbing Yuuya his "moral enemy", coming up with almost absurd ways of beating him and bursting into fits of maniacal laughter seemingly at random. He is a very sore loser and despises those who are weak or stand up to him. He holds a particularly fierce grudge against Yuuya. As a result of all these traits, Kai is either feared or disliked by the majority of ordinary students, though he isn't unpopular per-say.

However, Kai is very much aware of the negative view people have of him, and seems genuinely upset by this, claiming that he works hard behind the scenes and that there is "more to him."