Art made by Bobby_Arts in twitter
The hand with the ring is from

This is a powered version of my OC Lahmu, his true form. If Gaur his master makes him a really ambitious wish, Lahmu needs more power to grant it, so his master uses his magic ruby ring, an ancient relic of the royal family of the monsters empire to give back his natural power.

The history of the ring is really old: it's a Gaur's family heirloom. One of his ancestors, a powerful dark sorcerer tamed a Djinn on one of his travels through the desert. After a long battle against the genie he finally found his secret name (Lahmu) and engraved it inside a red ruby, catching the wild magic creature inside.

Lahmu the Ifrit was tamed and promised to be always faithful to the royal family, although feeling anguish inside him to be a slave without freedom. Now he serves Gaur as his personal magic assistant using a weaker form (grey skin with red fur) going unnoticed like a common bugbear of the kingdom.
Unlike his previous masters, he feels more confident with Gaur, Lahmu does not serve him out of obligation, but for pleasure; he feels a lot of admiration towards his master, he is not able to resist his hypnotizing charms, he just stands in front of him and says:

YOUR WISH IS MY COMMAND, MASTER.