I like these weird little creatures. I doubt anything like this could be found in Kuramen, but enough of the world is still nebulous that there might be some echo; we'll see as it develops, no?
I particularly like the note about the hazards of injuring one; toxic alchemical mixtures, quasimystical vapors, and outright detonations. Could make for an interesting battle if a fight broke out near one for some reason; neither side wants to hurt the giant worm, for fear of what might result. Go to Comment
I was going to link it to Interesting Weapons- Non-Magic, but then I saw that you mention power-runes. What are they? Later on you say that they have no special abilities at all, so I'm a little confused.
...Otherwise they seem to be a nice addition to your expanding setting, solid explanations and dead-on. Sweet idea. Go to Comment