The entire scene of Natsume's death. It begins with her heroic self-sacrifice to save Harutora. While dying, she confesses her love for Harutora as he cradles her. She reminisces about the happy moments they shared together during their childhood as well as the times they shared with her as Hokuto. Her alter ego Hokuto congratulates her for finally express her feelings to Harutora. As Natsume passes away, she says her only regret was not being able to hear Harutora’s answer to her confession.
Suzuka's failure to bring back her brother, particularly when he Came Back Wrong and started to strangle her.
Harutora's awakening. The young man we followed in the beginning of the story - our protagonist - is essentially dead. What makes a specific person a specific person, at least mentally? It's their memories and life experiences. When Harutora awakens as Yakou, all of Yakou's memories are shoved into his mind, and while they don't replace his own they certainly dilute and override them. His personality completely changes, and while one could argue that some of Harutora is still there, the truth is that that person is mostly Yakou; indeed it's really that they are neither Harutora or Yakou but someone different born from the combination both. Which ultimately means that the man Natsume died to save no longer exits, her sacrifice - resurrection or not - was for nothing. Further adding insult is her survival now means that the man she is waiting for to return to her is gone, replaced by in mind by an ancient scheme. If this isn't the ultimate tearjerker then what is?
