- Karen's backstory is kind of heartwrenching. So's her death, in the TV series.
- Seishirou's death and the aftermath of it.
- Kotori's death in both the manga and in the anime.
- The end of the TV series.
- Kamui: So... I'll die... and entrust my wishes to you...
- The TV series scene that has Subaru recovering from the Angst Coma that he had after the death of Seishirou, risking his life via Taking the Bullet for Kamui, and then telling Kamui to not give up on his wish before he almost dies.
- Saiki's, Nataku's, and Inuki's deaths are all very upsetting (but the last one comes back, so it's okay).
- Nataku's death is even more upsetting in the manga, where he dies in an Heroic Sacrifice to save his "mother figure" (Karen) from his "father figure" (Fuuma), thus fulfilling his Wish. Even Fuuma can't help respecting that as he explains Nataku's reasons to Karen and then spares her for the time being, and Karen mourns Nataku's death.
- Sorata's death is saddening in the anime, and it is made even worse when Arashi pays a visit to the shrine where he came from and sees what he wrote for her, placing her head against it.
- Satsuki's, Kuzuki's, and Yuto's deaths. Specially Yuuto's, in both film and anime: in the first one he's killed in one of the worst ways EVER in the film, and in the second he dies from the injuries Karen inflicted him before she also kicked it, recalling his chat with Satsuki about death and mourning. And lamenting that he won't be able to join her and Kanoe for tea any longer.
- Kakyou Kuzuki is a freaking walking tear jerker. If anything, he was already a woobie in the manga but the anime amped this Upto Eleven upon making him an Ascended Extra in the OAV — not only it explains his backstory and reasons, but it shows him trying to save his girlfriend Hokuto before Seishirou offs her. And not only he fails, but he gets shot for all his trouble.
- Hinoto's Heroic Suicide and her actual death in Kamui's arms are damn sad in the TV series. But what absolutely kicks it into Tear Jerker is Kanoe (of all people, KANOE) sensing it, and being driven to tears.
Tear Jerker / X/1999
Where to start?