Leviathan

Leviathan is one of the Four Beasts alongside Behemoth, Ziz and Bahamut, Heretics with unknown goals. In contrast to her fellow teammates, Leviathan is not much of a formidable fighter, as such she is mostly seen accompanied by an another Four Beast member. Fitting the sea serpent she is named after, Leviathan uses the Dark Matter, a viscous dark liquid made out of nanomachines which she uses to thrive herself as well as transport anyone she can trap within the liquid. Ordinary humans who are submerged in the black water would usually die by the pressure much like a regular water, save those with something special about them. However, the liquid by all means will lose its viscosity when exposed to Vapaus, particularly those who carry the blood type that synthesizes it. Leviathan has shown to be capable of transformation although initially, it was rather incomplete. However during Gluttony's ambush in order to devour Only One, Leviathan has a transformation akin to a crocodilian beast.