Kanshu (Lit: Coffin Guard) are a type of new creature that originate from an unknown source, otherwise known as the "Source of Infection". Kanshu are made through a virus which can travel through electromagnetic waves, and it recently revealed, or perhaps reminded, that they are not limited to only cell phones, but can also infect through Television, radio, and speakers. The virus takes over the conciousness of the infected, effectively destroying it. How the Kanshu communicate or coordinate their movements is unknown.
Most Kanshu reproduce by sending out signals to phones in the nearby vicinity. Anyone who picks up their phone there and then will die and be revived as a Kanshu themself. Howeverm, as stated above, the Kanshu producing virus can be sent over all types of electromagnetic waves. The reason this has not been the case is because Karasawa Shirou, the original source of infection, limited Kanshu reproduction to cell phones to lower the guard of NEFT.
Kanshu can also be created by Coffin Princesses and gather memories for them to absorb. An older Kanshu is called a Kamogari and is extremely powerful, with an extremely hard outer shell, usually colored black.
Kanshu are highly dangerous as they cannot be killed by bullets or any material weapons, but only by a special weapon called Jinki. However, it has been stated by Kanzaki and various other Jinki Users and support units that the biggest threat isn't the Kanshu themselves, but the rate that they can "reproduce".