* Mikage's death. Teito can't stop crying after it.
* Teito's suffering from PTSD and depression.
* Literally everything about the Raggs War is depressing as hell.
* Ayanami's story is sad, despite being the main villain. He fell in love with the Chief of Heaven's daughter, Eve, despite not being able to have feelings. Because he thought about loving her, a bug was created inside him, and so the Chief put him in prison. Eve came to rescue him, but [[TakingTheBullet died while shielding him from a bullet]]. She fell in his hands, and like any other thing that physically touched him, she turned into a skeleton. The Chief accused him of murdering his daughter and took his powers from him and created the Seven Ghosts. When Verloren fled from Heaven to Earth with Eve, Eve disappeared, and the Ghosts sealed his soul and body away using the eyes of Raphael and Michael; putting his body in Pandora's Box and making his soul reincarnate repeatedly, without his memories as Verloren. However when Ayanami/Krowell, the third prince of the Raggs Kingdom and Verloren's latest reincarnation, went to a ball, the seal on his soul was released by the brainwashed Raphael, and so he regained his memories. He murdered his mother, was forced to leave the family, murdered his brothers and continued to pursue his goal of finding Eve. He became Chief of Staff, but lost his beloved Begleiter in the war, as [[TakingTheBullet he died in the same way Eve had died]]... In the end, Ayanami couldn't find Eve, since she had turned into the light in all human beings. After getting cut down by his own scythe, he died, but got forgiven by the Chief and went to Heaven. It is sad, cruel and bittersweet...
* Ayanami sure as hell got a sad story, but the rest of the Black Hawks didn't have it easy either.
** Konatsu was disowned by his family for not being a Warsfeil. Though he made his life a living hell, Hyuuga was the first person who accepted him as who he was. Which is cute and happy and all, but watching Hyuuga explode into tiny pieces and die in an attempt to protect Ayanami and Konatsu definitely wasn't easy, was it? Thankfully he came back thanks to Labrador, but it's doubtful that Konatsu will ever be able to forget the sight of his boss dying, along with their co-worker betraying all of them.
** Like with Konatsu and Hyuuga, the first person who accepted Kuroyuri as who they were was Haruse. But when they infiltrated the church, Haruse ended up getting weakened by Labrador's flowers and getting his heart stolen by Michael. He was basically in a coma-ish state... At least Ayanami and Castor brought him back...
* The ''Hausen House arc'' has many moments. Teito finds out about Castor's (or Xing-Lu's) childhood... Since he was the Hausen's heir, one of the God Houses, he had a strict upbringing... his father was cold to him and only his mother was allowed to be openly affectionate towards him... He was young but he had to protect the Raggs royalty and eliminate spies and traitors, he created dolls to ease his loneliness but was unable to smile or cry until he met and befriended Razette.
** The way Castor and Lazette met is rather heartbreaking. He had just encountered a gruesome scene and she was basically kept as pet
** From the same arc as above, the sad and desperate situation in which Castor's father finally showed how much he loved his son... after being distant towards him for most of his life, he showed the depth of his paternal love and the measures he would take to protect his son... since, after siding with Raggs and losing the war, they had to offer the head of their clan's leader as a token of peace to the Barsburg Kingdom.
** ''"I want a love that would change my life"'' Castor's dearest wish... He only desired to live a simple life along with the people he loved...
** When his father attempts to kill Lazette (who changed her face to look like Castor's) so he could deliver her head instead to the Barsburg royalty (as they demanded after Raggs lost the war) Castor pulls a heroic sacrifice while thinking those exact same words.
* Labrador's backstory is also sad... or rather, more painful than sad. That poor boy spent his life suffering from a deathly illness, knowing damn well he was going to die. Even so, he remained cheerful and wanted his adoptive siblings to be happy. He knew his foster sister, Lirin, had the same illness, so he did his best to help her. In the end, he ended up sacrificing himself to the Flower of Eden in hopes of making Lirin feel better, which... really didn't end up well. Not only did he get devoured by that.. thing, when asked whether he knew this boy or not, his brother, Lem, said he didn't, since he wouldn't be able to help Lirin otherwise. Labrador (or, Ilyusha) was FROZEN ALIVE, while getting eaten by a plant and still suffering from the illness.
** What makes it even worse is that the flower didn't help at all and Lirin still died in the end.
** Lem's reactions are also heartbreaking...
* Frau's backstory. He grew up without a family, found home in Guido's ship, Aegis, watched as it fell in the war, caused his friend, Magdalene, to die protecting him, was the only surviving pirate... He then got Verloren's Scythe put in him almost right after, and then died.
* Frau and Teito having to leave Capella behind. What makes this even sadder is Capella saying "we'll meet again for sure", as Teito has since died and Frau has become the Death God.. Oh well, at least he can play around with Teito's little reincarnation!
* Ouka's backstory...
* The chapter where Teito visits Mikage's family. His older brother, Kokuyou, and younger sister, Rinka's, loving attitude towards Teito, his younger brother, Kohaku's, rage, both towards Teito and his own self (for giving Mikage the scar that forced him to join the military) and his father hugging Teito and thanking him for saving his son... And how Teito didn't even know Mikage had died in his stead... How even Shuri was upset over Mikage... It's all so heartbreaking...
* Landkarte's story is sad in its own way... Ea's too...
* The ending... Teito and Frau going through Seele...