Heroes Anonymous 20XX
Probably best that we can't see it
‘Affectionately’ nicknamed ‘Hugo’ by Arturo Erikson, Hugogggyoth is an ancient god that rivals Vlaire‘s parent/patron deity/whatever. Hugo seems to need Arturo for some reason, and has tried several times to capture him. What Arturo is needed for, he doesn’t know, but Vlaire assures him it would be very bad.
Hugo does have a cult dedicated to reviving the ancient god, but have so far not succeeded (maybe that’s why they need Arturo?). With the proper rituals, Hugo can send its children/appendages/whatever they are (similar to Vlaire) into our reality for limited times, much like the tentacled horrors that attacked our heroes one day on the way home.