Seizetsukyōsei (悽絶共生, Ghastly Symbiosis) is a unique, hiden Kekkei Mōra technique of the Rasen Clan that allows the user to control their existential physiology, and thus, break their body down on a energy level and manipulate their particle, molecular and genetic makeup. This allows them to merge with other forms of energy, one another, other objects and targets and it is the predecessor to Sakon and Ukon's Kekkei Genkai. It first appeared as a freelance Kekkei Mōra technique in its first generation of wielders before becoming eventually becoming an independent Kekkei Genkai in wielders succeeding Jinkyoji and Jinkeiji Korimachi. It also allows the user to control the energetic and particle makeup of targets, within a certain vicinity of the user, unnoticed.