Theory on the identity of the twins, as well as Seal and Break.
If we examine related keywords in the story, such as "twins," "Yomi," "Break," and "Seal," we can see a close connection between these keywords and the Japanese mythological figures Izanagi and Izanami.
Izanagi and Izanami are creation gods in Japanese Shinto mythology. They are twin siblings and also husband and wife.
The story goes like this: *"*After giving birth to the fire god Kagutsuchi, tragically died from severe burns. Grief-stricken, Izanagi decided to travel to the land of the dead (Yomi) to find his wife and bring her back to the world of the living.
When he found Izanami, she explained that she had already consumed the food of the underworld and could not return to the world of the living. However, she was willing to negotiate with the god of the underworld for a chance to return, on the condition that Izanagi must not look at her while he waited.
Initially, Izanagi agreed to wait. But as the wait became increasingly impatient, he longed to steal a glance at her. Breaking their promise, Izanagi stole a glance at his wife, only to find her a rotting corpse.
Izanami, deeply ashamed that her husband had seen her decaying body, enraged, sent the army of Yomi to hunt down Izanagi. Izanagi fled back to the human world and moved a giant rock to "seal" the entrance to Yomotsu no Hirasaka (the boundary between the human world and the underworld).
In that instant, Izanami vowed to curse the human world, taking 1000 lives every day. Izanagi responded that he would ensure 1500 lives were born every day."
Izanami wanted to "break" the "seal" Izanagi had placed on her and unleash her curse upon the human world.
Izanami symbolizes "death," while Izanagi symbolizes "life."
So far, we have witnessed:
- The power of "Break" is used to sever the heads of the enemies. Symbolizing "death."
- The power of "Seal" is used to seal a person's lifespan, granting them immortality. It symbolizes "life."
What about the "Break" and "Seal" Daemons? As we've seen, they're different than the other Daemons that they don't serve a single master. But each half serves one master. I don't know if the word "serve" is correct, because when Asa got the power of Break, what the Daemon said was "accept me". Which means that "Break" and Asa are becoming one.
Seal and Break Daemons might be the manifestation of Izanagi and Izanami's will respectively.
As the story progresses, we can anticipate that:
Asa will gradually be consumed by Izanami's evil and become an antagonist.
Yuru, in order to save her, will use the power of "Seal" to seal everything away, completely ending this vicious cycle.
Conclusion: I believe that Yuru and Asa (and all the previous "destined twins") are reincarnations of Izanagi and Izanami. The repeated reenactment of these events is to resolve it once and for all.