Made in Abyss Chapter 023

A Dreadful Experiment is the twenty-third chapter of the Made in Abyss manga series.

Synopsis
Nanachi drags Reg back to their hideout because he passed out from using the Incinerator. They complain, but believe they have finally found an answer to Mitty's problem.

In a flashback, Nanachi's past is shown. They were once one of many poor, seemingly orphaned, children. Bondrewd came to them, offering them the chance to assist in his research. Nanachi agreed because they wanted to see the depths of the Abyss. The children were sent to the 5th layer via a large container guarded by Delvers working under Bondrewd, also referred to as Umbra Hands. Along the way, an eager girl named Mitty tries to befriend Nanachi, who is resistant but willing to talk. Nanachi doesn't want to go back to stealing and looking through garbage for food, but Mitty thinks that is a useful skill, since there are treasures to find in the Abyss. Nanachi is very knowledgeable on the Abyss and able to read its rarely understood language, which amazes Mitty.

The children are kept in a single room, until Bondrewd comes and selects one to aid him. Gradually, the number of children decreases, until only Nanachi and Mitty are left. When Mitty is taken, Nanachi asks to go as well, but Bondrewd tells them to wait. Nanachi sneaks out anyway, and overhears a debate between Bondrewd and one of his Black Whistle assistants. The Black Whistle says it is inhumane to use children this way when they cannot possibly return to the surface, but Bondrewd insists this is irrelevant since he isn't using the children as humans. Nanachi is horrified.

Bondrewd stands before an elevator with two platforms. Mitty and Nanachi have each been sealed into a tube on one side. Bondrewd explains that this is an experiment to test the curse of the 6th layer: death or loss of humanity. The platforms are designed so that the full impact of the curse will be thrust onto Mitty. He warns her that if she dies halfway through, Nanachi will also be hit by the curse. As the elevator lowers, Nanachi admits that Mitty is a precious treasure they don't want to lose. In the 6th layer, the misshapen failures of the experiment gather around the tubes. As the elevator rises, Nanachi begins to grow fur all over their body and can only watch helplessly as Mitty loses her humanity. After additional "testing" Bondrewd discovers that Mitty cannot die: she simply regenerates from damage, though her form is less stable each time. To save Mitty from Bondrewd, Nanachi runs away with her, and they settle down in the hideout. Nanachi searches for a way to kill Mitty and end her suffering, but they only succeed in hurting Mitty. Delvers beyond help serve as test subjects and Nanachi buries their bodies behind their hideout.

Nanachi tells Reg about Sparagmos, an Artifact of Bondrewd's that sounds suspiciously similar to Reg's Incinerator. This was the only weapon that managed to inflict damage that Mitty could not regenerate from. Reg is uncomfortable with killing Mitty, but Nanachi insists that Mitty's soul is trapped. Reg asks for more time to think about it. Nanachi assures him that they will keep treating Riko, whatever Reg decides. Reg is worried what will happen to Nanachi once he kills Mitty.

Character Appearances

 * Bondrewd
 * Umbra Hands /
 * Mitty
 * Nanachi
 * Reg

Bestiary Indexing

 * Orb Piercer

Referbacks

 * Ozen warned Riko and Reg to avoid all White Whistles, and particularly Bondrewd, in Chapter 017. It is unclear if she was warning them to avoid him in a general sense, or if she knew specifically of Bondrewd's habit of using children in his experiments.
 * Oddly, Nanachi's claims that Riko interests Mitty in Chapter 021 make more sense now, given their similarities. Though Mitty and Riko have never met properly, they both aggressively befriended someone who interested them (Nanachi and Reg), had largely optimistic attitudes, and suffered a life-altering tragedy within the Abyss.
 * The tombstones that Reg saw behind Nanachi's hideout in Chapter 021 belong to the various delvers they tested medicines and poisons on, in their attempts to help Mitty die.

Adaptation
This chapter was adapted into the following episodes of the Made in Abyss anime series without any major changes:
 * Episode 13: The Challengers
 * Made in Abyss Movie 2: Wandering Twilight