Kaikin (戒禁, Keeper, lit. "Prohibiting Commandment") is a rarely used Unrestricted Spell which acts like a barrier or trap to protect a Mystes, which is a container for a Treasure Tool. The creator derived it from a spell they had used to put a Mystes under their control.
To protect the Treasure Tool that the Mystes is storing, the Mystes' creator inserts the spell into the Mystes straight after creating it, Therefore, the Treasure Tools requiring a Kaikin are mainly limited to ones used for battle or very dangerous ones.
The strength of a Kaikin is proportional to the strength of the applier's will, and an exceptional Kaikin would make it possible for the Mystes to move around inside a Fūzetsu.
A Kaikin spell can have many different effects. According to Mare, it could capture beings who interfere with it, or steal their power, or apply damage. Mare also possessed an Unrestricted Spell Gemeinde, which could bypass a Kaikin.
|Johann||Reiji Maigo||If anyone other than Pheles touches the seal, they are attacked|
|Yūji Sakai||Reiji Maigo||Steals and absorbs the power of Denizens who attack the Mystes|
|Tenmoku Ikko||Nietono no Shana||Prevents targets from moving|
The Torch Yūji Sakai became the Mystes for the Reiji Maigo, not due to being created to become a Mystes, but rather as a result of the Reiji Maigo's random transfer from somewhere else. Nevertheless, Yūji still had a Kaikin. His Kaikin was extremely strong, able to tear off the arm of the powerful Crimson Lord, "Thousand Changes" Sydonay. It was also thought to have been applied by Pheles, by it activated against her as well.
According to "Corpse Retriever" Lamies' analysis, the Kaikin's function of absorbing Denizens' power was added as an absorption insignia to the Reiji Maigo, which had the Psalm of the Grand Order inserted into it, by the changing Tyrant I. The cause of this absorption was unknown, but there is a high chance that when this insignia, which was in a dormant state, activated, the Kaikin interfered with it as well and was thus altered.
However, it was later discovered that this was an intentional change made by Johann, who was sealed within the Reiji Maigo. After Johann was released from the Reiji Maigo by Pheles, the Kaikin had mostly stopped functioning.
In the AnimeEdit
- In the first season, Yūji Sakai's Kaikin did not activate against Sydonay.
- In the second episode of the second season, it was activated towards Mare, who unlike in the game, wasn't aware of the Kaikin and Gemeinde wasn't an Unrestricted Spell that could counteract it.
- In the third season, it wasn't stated what happened to the Reiji Maigo's Kaikin.