In Shikkoku no Sharnoth -What a Beautiful Tomorrow-, when M goes to "devour" a Metacreature, Mary describes that what is M is using is an equation with some of the patterns being Monumental Kadathian.
In Sekien no Inganock -What a Beautiful People- which takes place before Shikkoku no Sharnoth, Gii and Kerkan both use the Phenomenon Equation, Gii uses a healing one while Kerkan uses a destruction one however Gii mentions that there are many other Equations that one could use.
So what is the Equation M is using?