Shirushi

Shirushi ((印, lit. Sigil) is an ability unique to the seven Nana Shadōzu (七シャドーズ, lit. Seven Shadows) of the Imawashii Criminal Organization, granted by the Shadōkingu (シャドーキング, lit. Shadow King) himself. When concentrating, the sigil appears on the area it was branded and begins to glow a faint red color. This act gives the user access to increased spiritual power that is akin to a Shinigami releasing their Zanpakutō and an assortment of dark powers that vary with the user. An unknown side-effect of this sigil is that those branded with it can be controlled to an extent by the one who branded it.

Behind the Scenes
The Imawashii's Shirushi is the sigil thought to be belong to Lucifer. If this offends anyone, then I apologize.