Sherumi and Menae

"Menae"

- I wonder why we can't go together...? But soon enough we'll understand... We're twins after all.

Menae & Sherumi are twin sisters that appeared in Distant Writings 1undefined and 2undefined (brief single-page explanations of Abyss characters that appeared at the end of chapters 39 & 40) and a brief appearance in Made in Abyss Side Story Chapter 003. It is briefly explained in Distant Writings 1 that their conversation was located in the East District of Orth, due to this it is theorized that they were most likely born and raised in Orth.

Appearance
They are nearly identical twin sisters with long thick hair (of an unknown color) and bangs that cover their forehead.

Distant Writings 1
They discuss how there were tens of thousands of pictograms drawn on Abyssal relics and how the simple ones were chosen and applied to the sounds of the official language which became the Abyssal writings that they now currently use. They also talk about how each of the characters originally had "sounds" and "meanings" and were called ideograms.

Distant Writings 2
They mention how delvers use simplified versions of some of the Abyssal Writings characters as codes; there are two types of characters mentioned: "Netherglyphs: Abyssal Writings" (characters used regularly), and "Beyondglyphs: Distant Writings" (seemingly endless newly discovered characters). They also talk about a character unknown to them, "Ilblu" or "Iruburu", and wonder if the meaning of it would be known by the time they grow up.

Made in Abyss Side Story Chapter 003
After Jiruo's talk with Ozen about the Birthday-Death Disease and other various topics, the next page Menae is suddenly shown talking to a deceased rotting Sherumi covered in flies in a dark room, she questions if Ozen would return again. After talking about why they can't go together, Menae stops talking and presumably dies. After this a shot of Reg is shown where he sees nameplates fall from the sky; one of these nameplates say: "Sherumi returns to the Abyss".