While normally Kotonoha targets her main rival and ex-friend, she has accidentally caused a few deaths as well and blindly targets anyone if pushed past her limit.
Due to her dependancy on Makoto, Kotonoha doesn't intentionally target him in most cases.
After snapping when she finds out Sekai is with Makoto she approaches them at the train station and shoves Sekai onto the tracks. Makoto attempts to help Sekai but before he is able to get off of the tracks himself the train shows up.
Besides accidentally getting him killed, she is shown targeting him twice in comical fashion during the spin-offs when he sexually interacts with Kokoro, her little sister. She intentionally only kills him in the second case, stabbing him with her Kunai and setting the building on fire after escaping.
While she did not kill Makoto she does decide to decapitate him after finding his bloody corpse.
She initially shows a forgiving side after Sekai and Makoto apologize for dating behind her back and then being dumped by Makoto. However, her mental state is unwilling to let it go and she makes plans to attack Sekai- only to accidentally stab Makoto and send him to the Hospital.
Her common target as of a result of causing her so much pain as the other end of the love triangle.
Most of the games deaths involve Kotonoha targeting Sekai. The most common and infamous death known as the "Bloody Ending" involves Kotonoha approaching the couple and their friends on a bridge crossing. She remains silent as they awkwardly try to speak to her, but in seconds she cuts Sekai's throat, causing her to die a slow and bloody death while everyone looks on horrified.
In another ending she uses Sekai as a leverage to get off of the tracks she pushed her onto. Makoto helps Kotonoha up and Sekai drops her cell phone, but just as she gets it the train hits her.
Kotonoha quickly realizes it was Sekai who killed Makoto and sends her a text with his phone. They meet on a buildings roof and she reveals what she did to the corpse with the head in her bag, shocking Sekai. Sekai attempts to attack Kotonoha, no longer feeling safe but Kotonoha easily kills her, then cuts her open to see if she lied about her pregnancy before fleeing the scene.
Feeling that Sekai was untrustworthy after being dumped by Makoto, she plots to kill her.
The main protagonist of the second game, a young man who liked Kotonoha and pretended to be a girl named Yuu in hopes of exposing Makoto's lecherous ways. If Kotonoha finds out Makoto has feelings for Yuu, she targets "her" and kills him in a few routes.
Yuki's older sister who Kotonoha approaches in one route. Chie claims to be Yuu in order to spare her brother, ending with Kotonoha killing her with a crowbar.
In one ending from a spin-off game, she claims to be pregnant with Makoto's child. In response Kotonoha is seen pulling out a sharp object as the scene ends.