Compared to the illusion spell that he put up to fool Blake and his group or even Vera's last second improvised spatial rune formation to teleport all of them to the current isolated space, the amount of nether that gathered all around him was definitely lesser.
However, the difference between the current spell that Vera had just released to the world and those massive rune formations was that the massive rune formations encased a large area with their equally large amount of nether.
But in the spell's case, although there wasn't as much nether gathering around the scrawny humanoid demon as the rune formations, the amount of nether that gathered in a single area, around the scrawny humanoid demon, could be said to be denser compared to those rune formations that spread out the gathered nether around a large area.