Dushkrivya

Dushkrivya is a term for the ritualistic spell that devs perform to become rhakshasas . The spell always requires killing another or multiple other devs. The spell was discovered in a bygone time. Some say it was taught by an angry spirit  who wanted to tear the dev race from the inside. But over the centuries of experimentation and documentation, devs discovered multiple ways to commit dushkrivya, adapting it so they do not just become rhakshasas, but become rhakshasas with particular features and abilities. Seven of the eight rhakshasa tribes identify themselves through the results of their own version of dushkrivya. The Kalandala method involves killing their victims slowly while staring them in the eye the whole time. The Pidmaya method requires deception that convinces their victims to kill themselves, and the Gorsath requires violent dismemberment in a particular order.
If devs make any error in committing any of these more particular dushkrivya, they will still become rhakshasa as long as their victims die during the spell, but they will not get the results that the tribe demands to be accepted by them, and will themselves be victims to a curse  that can far outweighs any powers they gain.