- Ah, Chidori. She continues to love her childhood friend years after he's seemingly stopped caring about literally everything around him and for years she tries to get him to emote like he used to to no avail. Then she's kidnapped, forced into a questionable experiment, and then is faced with the fact that the one who has managed to grab her friend's interest again... is not her.
- Maki and Ruru. She and Ruru are seen to be very close, and then Ruru dies, causing Maki to lose interest in everything, including relationships with other people. This is also the reason she stopped writing manga.
- After Maki's complete breakdown in episode 6, Nico notes that because the Kizuna system divides their pain up, whatever Maki was feeling would have been seven times worse if she'd had to face that alone.
- Episode 9 is one big tearjerker tied up together. Everybody realizes that none their feelings are returned, and everybody is hurting one another, Katsuhira ignores Chidori's feelings, who is oblivious to Tenga's feelings who is again, oblivious to Nico's feelings. This episode last scene gets everybody feeling so much emotional pain they all fall to the ground only capable of saying "it hurts".
- Episode 10 seems like it'll be a less stressful episode after the sorrowfest of Episode 9... and then we learn the truth behind Katsuhira's Kizna connection with Sonozaki. Katsuhira and Sonozaki were two of the original 19 children used for the first Kiznaiver experiment. With 19 people to split the pain between, the negative effects on the children should've been near nonexistent - until a single child took on the sensations of every subject, and the other children lost their sensations, and in some cases, stopped functioning entirely. The mysterious and intense pain that Katsuhira sometimes feels that none of the others in his group can is Sonozaki's pain that she's been suffering from every single day for twelve years. That flashback Katsuhira had at the beginning of Episode 1? Sonozaki was trying to commit suicide probably of the agony or to perhaps return everyone's pain and sensations that she's absorbed. She tries again midway through Episode 10. When Katsuhira realizes this and remembers everything, including how Sonozaki used to be an incredibly cheerful girl... his sobs are heartbreaking.
Tearjerker / Kiznaiver