The Akuruka (アクルカ) are special masks created by the Mikado, based on research from the Iceman Project after he found some of the defects and decided to improve on it. The user and their beast form are refers as Akuruturuka.
These masks originally intended to be used for the enhancement of human physical abilities but the prototype masks was proved to be too strong so he had to create the lesser ones with weaken function. The masks can improve the abilities of the wearer and give them the ability to transform into the powerful giant bipedal beast, the downside being that they drain the user's life until the user turns to salt. When worn by the demihumans, like Mikazuchi, only 30 percent of their power can be used, but when worn by an original human, like Haku, 100 percent can be used. When worn by an old human, they fused to the wearer's face and become impossible to remove.
Known Akuruka
Lost Flag[]

An unnamed Akuruka that appears to be a mass-produced made by Surikuri show up in the story. However once don these masks, the users immediately turn into their beast form.
Unlike the one in the main series, these masks can be used by anyone but Shakokopulu race having the best compatibility with it.