If I was Marverni, I'd use slingers.
By the way, good idea to link Jinn with Catharsis/Anthrax. I didn't thought of it. This could be nation with relation to him similar to that of Abyssians to Rhuax. But they certainly shouldn't be directly linked to Abyssians - what's the point?
Djinni are spirit beings in Islamic myth, and are said to live exactly as we do, however in a parallel spiritual realm named Gaib. Some of them don snake form and live amongst mortals, so serpents are a sign of spirits and djinni.