At least if it's a spirit that aims for everything not just yukkuri, for all we know the hands could be a representation of all the world's hatred for yukkuri that would also explain their over the top deaths that sometimes defy physics and biology...
Of course it makes me wonder why the world's hatred picks on this somewhat nice looking Marisa instead of going around torturing shitheads and scum yu's, unless the asshole wizard that created/modified them installed something that makes any yu, no matter their karma siding, be a beacon for the world's hatred to aim for.
If it is what I said, then you just can't exorcise it since, again, it's the world's hatred, not just "ghosts", but some metaphysical part of the world with emotions.
This whole thing reminded me of that story on which Eiki explains that yukkuris are actually the spirit of the wicked jammed on a pastrie and that all the bad things happening to them is part of their typical "bad people soul's" punishment but since hell was full they had to send them to the living world to face their punishment.
And this is the picture of her last momentsI brought my pet Marisa to the sea and she drowned.
It was a clear day without wind or wave. I'd also prepared her against water. Even so, she still fell into the water.