He's getting paid to make Piasma suicidal.

He's a demon. He's getting paid because influencing people is his specie's usual profession because of their abilities. Cruor here can really get in people's head and affect their confidence in themselves and others. Another demon, Sinew, is his partner (parter, although they work against each other) who tries to keep Piasma stable and happy. And if Piasma ends up offing himself Cruor gets a bonus in his pay, if Piasma becomes too stable for Cruor to affect Sinew gets the extra pay. It's literally just their job.

It's cum. I mean what else would it be??