I think he's cool I guess I mean I like how he's the main villain despite being incarnated into the body of the main character and can still use his own technique when he comes out as well as his domain I think his domain fits him perfectly which I know is quite literally the point but it's just so cool and the fact that there's a possibility that his domain is inspired by atomic explosives such as nukes also really intrigues me and represents how destructive he can truly be. I also love his Buddhism symbolism such as being based off of a literal buddhist legend about a conjoined twin, the theory of him being Buddha himself since he has reached true jujutsu and true jujutsu is seen as enlightenment which Buddha reached too, as well as having a design that looks close to Asuras in Buddhism, and his domain expansion hand symbol being that of the King of Hell's hand symbol. I also like how his hand symbol contrasts with Gojo's since Gojo's domain expansion hand symbol is half of the Queen of Heaven's hand symbol. The way that he says he finds love pointless but still experiences love, just in a completely different fashion than what modern humans would consider love, through showing respect and admiration to his opponent depending on how strong they were no matter his strength state at that time. Also what we know of his backstory and him eating his twin in the womb probably lead to him being an unwanted kid, as his parents may have took it as him being a worthless monster, causing his hatred for anyone to build up. And him eating his twin shows that he was cannibal from the start which is another detail I really like. But yeah he's cool I guess I don't think too much about him