| This article contains contents that are not localized in North America or Europe.|
The following contents have not been released in the English language and are based on data from the Japanese version of this game. Details are subject to change at any given time.
Arca is a ubiquitous organization associated with the game's church system, which is heavily structured upon the notion of repentance, particularly the belief that Narakians should beg for forgiveness from Devalokians in order to return home. Early in the story, Arca captures and detains Avatars under the guise that they are a threat to society. However, it is later revealed that Arca uses Avatars for experimentation or weapons of war, be it through combat or powering combat machines. Mathias herself seeks information regarding the location of the Manifest, while two of her subordinates, Thitose Cxarma and Sian Tenebro, operate somewhat differently. Thitose focuses on recruiting Ruca Milda to the organization because of the love she has for him, which carried over from her past life as Sakuya. Sian, on the other hand, works in tandem with Mathias in locating the Manifest, believing that Mathias will create an ideal world with its power.
- Mathias - The mysterious woman who serves as leader of the cult organization.
- Thitose Cxarma - A young woman who feels that Arca is one of the only safe places for Avatars.
- Sian Tenebro- A naive young boy manipulated by Mathias into doing her bidding.
- Arca derives from the word Arcadia, which is used when referring to a real or imaginary place offering peace and simplicity, a comparison solidified through Arca's similar appeal in the story.