As a Moments page, all spoilers will be unmarked!
Where to even begin...
- Nat and Riko's arguments in Episode 3. Nat understands full well that Riko going down into the Abyss is suicide by all accounts. Considering he has a crush on her, the thought of never seeing her again is painful and he says some hurtful things that he regrets before she leaves.
- Reg saying goodbye to the others was painful for him as well. He'd been there since he woke up, so they felt like family to him.
- At the outpost, Riko learns that she was a stillborn baby in the Abyss. It was only through the relic she was placed in that she began to move again, meaning she's a living corpse with a drive to go to the depths of the Abyss.
- On the fourth layer, Riko gets poisoned and Reg has to pull her up to avoid the creature responsible, Orbed Piercer/Orby. Not only does she start bleeding from every hole, but she starts hallucinating and begging him to cut the arm off. He has to break her arm but couldn't cut it right and she ended up nearly dying, if not for Nanachi. Reg having to be the one to do it nearly breaks down as well. His desperate, despairing cries are especially harrowing in the anime.
- Mitty's fate. She was warped by the curse in an experiment and then put into a state where she couldn't die, but would feel pain and suffering. Her soul, according to her friend, was essentially trapped in her body, and while she had Nanachi to take care of her she would eventually be left alone when Nanachi died one day. So when Reg had a means to kill her, Nanachi begged him to Mercy Kill her and broke down crying afterwards.
- Oh dear god, the killing scene itself. We've been made to care about what's essentially a blob that used to be human. Mitty also provides some means of comfort for Riko during her unconsciousness. Then Reg finally agrees to the Mercy Kill, and we're forced to watch him do it with tears in his own eyes for crimony's sake... Not to mention Mitty was surrounded by stuffed animals in her final moments. The scene hits especially hard if you've ever had to put down a pet.
- Nanachi screams for Reg to stop just before Incinerator fires and then runs to embrace Mitty, while crying themself. We're lead to believe that Nanachi has had a change of heart and will go looking for some relic to restore Mitty instead. It's a great development of their character arc, right? Wrong! The Mercy Kill goes forward. Nanachi is so devastated that if Reg hadn't forced Nanachi to promise not to commit suicide, they just might have.
- Hell, look at it from Mitty's perspective too. On some level, she is aware of how Nanachi is caring for her but cannot do anything about it. The anime lingers on her in her final moments, trying to say something to her friend before being blown to smithereens. Whether it was fear, gratefulness, or something else, we'll never know.
- Prushka's fate. She's essentially made into a cartridge by her adoptive father, who raised her and watched over her, when all she wanted to do was help him. Worse, she's conscious while stuck inside of there and forced to watch her father fight with her new friends.
- Making this even harsher, we're given virtually an entire chapter showing Prushka's childhood. Bondrewd's nursing her to health, caring for her like a father, and teaching her about his work in the Abyss should seem creepy. The fact that it's made very clear that he sincerely loves her and he still decides to use her as a resource anyway makes it all the more heartbreaking. The culmination of the chapter, when we're shown Prushka's fantasy of Bondrewd sending them all off to the Sixth Layer with his blessing hits hard. Everything in her fantasy actually happens, but it's all wrong.
- Chapters 48 to 51 detail how the Ganja Corps founded the city of Iruburu. Where to start?
- First, Vueko's backstory. Her father was abusive, and constantly boasted about being "entrusted" with discovering the Golden City while beating her daily. Some of the abuse involves the usage of a brand.
- Once Vueko grew older, she found herself journeying with the Ganja Corps in order to find this Golden City. Along with Wazukyan and Belaf, there's a small girl that accompanies them named Irumyuui that looks suspiciously similar to Faputa. The first thing we learn about this girl is that she used to live in a village close to the Abyss. Why did she leave? Her mother disowned her and she was branded an outcast by everyone else after it was found she was unable to have children. Irumyuui and Vueko (whose own physical abuse left her unable to have any) quickly form a tight bond, becoming a surrogate family for each other.
- Irumyuui finds a cute animal companion as a friend for some time... before said companion is unceremoniously eaten by one of the Sixth Layer's predators. Vueko has to hold her back to keep her from being eaten too.
- As the Ganja Corps progressed into the Sixth Layer, they realized they were unable to progress further and decided to set up a permanent camp near a decent source of fresh water. They manage to find one with the help of the Interference Units, and all is well for a few days. That is until it is revealed that their source of water was an organism called "Mockwater", which calcifies the bodies of whoever drinks it and causes them to suffer intense diarrhea and pain. The first person we see affected is Irumyuui, whose hand is mangled and mutated from the disease. If they don't find some way to cure it quickly, Irumyuui and all the members of the Ganja Corps will slowly and painfully turn to stone.
- In an effort to stop the Mockwater disease, Wazukyan manages to discover a relic called the "Cradle of Greed", which grants the wishes of those who have simple desires, meaning that children are best suited to using it. So the three sages decide to give the relic to Irumyuui and hope that the problem is solved by morning. Come next morning, and Irumyuui seems like she's back to her normal self... except her hand is just as mangled as it was yesterday. As more time passes, Irumyuui begins to mutate further and further, eventually culminating in her giving birth to a creature resembling the animal companion that she lost. Irumyuui is finally able to have a baby as she's always wanted. The next day, the baby dies, not having the organs necessary to eat food. Irumyuui is in complete shambles over the child's death. The best part? She continues having more. And they die too. Irumyuui never gets used to seeing her children die, and her agonized expressions are heartbreaking to look at.
- The disease eventually catches up to Belaf and Vueko, who slowly start to die until Wazukyan feeds them some soup, which seems to subside the symptoms. What's the soup made of? Irumyuui's children. What's worse is that when we see her again, she's become so horrifically mutated that she can no longer speak. Even though her children still die, she keeps hugging them lovingly... then Wazukyan snatches one of her children and we get to see her horrifically wailing as he takes the child and cuts it up. Vueko nearly vomits having to look at it. Even after all of this, Irumyuui still embraces Vueko, who is utterly despondent as she can't do anything to help Irumyuui.
- Once Irumyuui sits down in a place filled with light, Belaf comes forward and asks for her to eat him, as he's realized that he's been feeding off of what was precious to her. Irumyuui grants this wish and he becomes a Narehate. The other members of the Ganja Corps, believing they can be forgiven if they do this, also offer themselves up to become Narehate.
- Then it's revealed that Wazukyan used another egg to transform Irumyuui into the state she's in now, granting his wish at her expense. Vueko, unable to help Wazukyan anymore, throws herself off a cliff. However, Wazukyan catches her, and puts her in the pit, which is revealed to be Irumyuui's head.
- Within Irumyuui's head, she's able to see what's going on in the newly formed village of Iruburu, where she witnesses the birth of Irumyuui's final child, Faputa, born from the anger and grief Irumyuui feels against the village for murdering her children.
- Finally, Vueko finds herself accompanied by the souls of the children that were either killed or died that Irumyuui never gave a name to. So while she sits alone in the pit, she names each and every one of the children in place of their mother, saying that she'll call their names "no matter how many times".
- Chapter 45 shows that there is a perfect Mitty clone in Ilblu village, possessed by one of the village sages, Belaf. Riko realizes that this Mitty, as Belaf claims, is truly a copy in body and soul, as she can sense her presence too. When Nanachi finds her and sees Belaf use her as food due to her immortality, they beg him to stop and decide to sell themselves for Mitty's sake so she will never suffer again. Belaf agrees with their exchange and puts them to sleep together with Mitty before Riko found them.
- In chapter 54, when Faputa attacks the village, Nanachi is given a difficult choice by Belaf—whether to stay with this new Mitty or to leave them forever to go with Riko and Reg. If Nanachi stays with Mitty, they'll have to become a part of the village and never be able to leave. On the other hand, if they choose to aid Reg and Riko, Nanachi will never see Mitty again as everything made in the village will disappear forever. However, after agonizing over the choices and remembering Mitty's last words before becoming a Narehate, Nanachi realizes how selfish they've become and goes with Riko and Reg. Before Mitty finally disappears at the border of the village, Nanachi tells her everything about their adventure so far, their experience, and that they're able to make new friends. And if you didn't think that was enough, they promise Mitty that they will meet again in the next life.
- The climax of the Iruburu Arc has Faputa's massacre plan Gone Horribly Wrong, where having Reg destroy the village barrier to let her in also allowed the beasts of the Abyss in, who proceed to slaughter the villagers, depriving her of her purpose, Zerg Rush her to shred her to pieces, and just as it seems she's going to be crushed to paste, Gabu performs a Heroic Sacrifice that causes Faputa to be Forced to Watch as he's smashed to death. The fear and sorrow in both her eyes and voice as every one of her reasons for living are taken from her really highlights how pitiful and tragic Faputa's existence was.
- When Vueko experiences the Hollowing effect of the 6th Layer due to the village walls breaking down while she's ascending, Pakkoyan performs a Heroic Sacrifice by grabbing and throwing her back down, despite knowing that going outside would kill her, leaving Vueko only able to tearfully utter her name as she disappears into nothingness.
- Vueko's death, and how. After getting slammed with the 6th layer curse, she can no longer physically speak, and spends the rest of the finale slowly languishing as she watches the destruction of the village and Irumyuui finally being set free. After Faputa wakes up, Vueko pitifully crawls over to her - to the point of Nanachi needing to help her - and thanks to Faputa's ability to hear her thoughts, she's able to tell her and reminisce about Irumyuui, which leaves her crying over everything that happened. It gets worse as Vueko's consciousness begins to fade and she mistakes Faputa for being Irumyuui, despite the latter obviously being gone at this point, and Faputa simply goes along with it as Vueko says that Irumyuui changed her as she finally dies. Even though Faputa had little prior connection to Vueko due to Irumyuui holding on to her memories of her instead of passing them on to Faputa, she's still utterly heartbroken by the loss and left wondering why she feels so sad. The rest of the group, who are also saddened by Vueko's death, walk over to comfort her. Faputa later creates a grave for Vueko near the remains of the village.
