Here are a collection of sketches I've put together for an AU for Hollow Knight I started thinking about awhile ago.
So in this universe the Pale King never created vessels, instead of learning how to harness the void he learned to harness the Nightmare Heart in an attempt to seal away the Radiance. No mind or will for the Radiance to influence if they've been burnt to a crisp by the Crimson flame; I know that's not how it works but I did need to make a few alterations for this AU to make sense.
Instead of a shade, Grimm has a flame and I based his nail upgrades of off the torches the Grimm Troupe use.
Like the vessels there were many Grimms, but only one was considered pure enough to seal the Radiance away, Nightmare King Grimm, or The Scarlet Knight they are known as in this reality.
The vessels aren't entirely gone however, they are the ones who run the Grimm Troupe here. Like with the Grimm Troupe the Troupe Master is replaced every now and the to start the cycle anew.