I literally can't sleep rn bc i'm thinking about Sukuna's parallels to Shiva. I'm still learning a lot about Hinduism, the foundational concepts of its beliefs and it's nature as a precursor to Buddhism which JJK is slathered with references to. (and an important disclaimer that Hinduism isn't a monolith, but a categorisations of many diverse and often contradictory denominations and belief systems)
The visual similarities are clear:
But in the text he reads as an Avatar of Shiva's status as the Destroyer, the being that destroys the illusionary world of Samsara for the universe to be reset. It reflects his role as the current administrator of the Kenjaku's merger, clearing Shinjuku of sorcerers to bring about a new form of life.
This status also implies a detachment from the Karmic Cycle, or enlightenment as it can also be described. Sukuna's achieves this via all consuming hedonism. He denies the world any attachments to him by refusing to do anything but what he wants, when he wants it. If he wants to eat, he'll eat. If he wants to fight, he'll fight. If something stands in his way, he'll utterly destroy it without hesitation. He isn't bound by any pre-conceptions or possible consequences, his actions are entirely dictated by his wants and his is entirely present in each moment he exists.
The nature of Sukuna's ultimate technique, furnace, also shares similarities with Shiva, who upon opening his third eye turns everything before him to ash.
This is a really shallow look into this similarities, but Gege is so pointed with his spiritual allusions in JJK that I always find myself interested in finding this small points in his characters.