* Eiji Tono, one of Kindaichi's classmates, commits suicide due to Miyuki who looks like her late sister, despite almost asking the real murderer who kills Eiji's sister to die. However, he was then seen again in ''The Undying Butterflies Case'' as he falls in love with one of the Maradame sister's as he seems to lost his memories about the previous case. After their marriage, the police decides not to arrest him for his previous case as he seems happy in this life of his now.
* Playing the Fool Case
** When Reika's been kidnapped, due to her trauma of seeing her real father being strangled, the kidnapper felt sorry for her thus becoming her father and treats her 'daughter' well despite being the kidnapper.
** In rage, Reika could not accept that his manager is his brother since he's a murderer too thus runs out of the heavy snowstorm. The manager manages to catch up on her and save Reika from an avalanche.
* Kindaichi the Killer!? Case
** The start of the case happens to fall a few days before Miyuki's birthday. Her attempts to remind Hajime about it fail repeatedly after constant interruptions. Hajime's run from the law continues even onto the day itself, with Miyuki worrying so much about him that she forgets about it entirely. That same night though, she receives a message from Hajime, telling her to go to the park at 11pm, where she finds a box containing a small cake for her, with a happy birthday message, from Hajime who had already left the park, which she tearfully accepts.