Riptiles are among the most common form of Rouge Demons. Riptiles spawn from those who chose the path of a Demon in order to become more powerful then a certain person. Thier morality and sanity are both lost at the cost of thier envious actions which allows them to be manipulated through the sin they commited to be created, which in this case is Envy.
Riptiles are created from Humans who wish to surpass a certain individual in strength in order to kill them. This envious action causes the Demon to loose all sanity and take the form of Jelousy; which is ugly and therefore transforms them into a Reptile capable of ripping anyone to shreads with its claws and teeth; hense the play on it's name.