Shinmai Maou no Keiyakusha Wiki
Ars Decidium
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Name Ars Decidium
Kanji アルス・デシジウム
Rōmaji Arusu Deshijiumu
User(s) Shiba Kyouichi

Ars Decidium is a unique power that Shiba Kyouichi possessed from the moment of his birth similar yet different from Banishing Shift.


Ars Decidium is a unique primordial power, which had originated from the universe before the current one came in existence and Shiba was born with after all the experiments to make a clone of Jin Toujou, as well as being the basis for his Ki Manipulation. It is similar yet different from Banishing Shift, with the main difference being that Ars Decidium grants Shiba multiple abilities instead of just one.

It is in a sense a specialized combat style the ten different forms including a final form, focusing on the Art of God Killing, which is applicable to both High-Level Gods and Demons.


Fifth Form

Fifth Form - Nine-Headed Kusanagi: This is the Fifth Form of Ars Decidium, where Shiba creates an assortment of magatama, which surrounds and entraps his intended target.

Eight Form

Eighth Form - Takemikazuchi: The Eighth Form of Ars Decidium, where all of the magatama release black and red lightning restricting his target before electrocuting him.

Tenth Form

Tenth Form - Kurikara: This is the Tenth Form of Ars Decidium, where Shiba uses his ki to create a four-headed hellfire breathing dragon.

Final Form

Final Form - Totsuka Blade: This is the Final Form of Ars Decidium, where Shiba combines all five elemental ki to create a sword able to releases a unique flow of energy, which can cut through concepts.


  • Ars Decidium is Latin with Ars meaning "Art" and Decidium meaning "Killing God".
  • The Fifth Form, Kusanagi is a reference to the Kusanagi-no-Tsurugi, also known as Ame-no-Murakumo-no-Tsurugi, a sword found inside of the Eight-Headed Dragon, Yamata-no-Orochi after being slain by Susanoo-no-Mikoto.
  • The Eight Form, Takemikazuchi is a reference to the Thunder and Sword God, Takemikazuchi.
  • The Tenth Form, Kurikara is a reference to the sword wielded by Acala in Buddhist Mythology.
  • The Final Form, the Totsuka Blade is a reference to the Totsuka-no-Tsurugi in Shintoism, four divine swords used by the major deities in the mythology.
    • The Totsuka Blade's unique energy flow might be due to the Five Elements, which has their own energy flow:
      • Fire motion upwards with an accumulative flow.
      • Wood has an expansive flow.
      • Water motion downwards and inwards with a conservative flow.
      • Metal motions inwards that has a contractive flow.
      • Earth motions inwards and centering with a stabilizing and conversing flow.