Transcript
1: Somewhere in a dark, strangely-built house, a circle of reptilian figures kneel in a circle, their eyes shut.
2: One of the lizards clutches their head.
Lizard: It’s gone… That was the last infiltrator we had in the facility…
???: Mmmnnnh… More memories lost. It can’t be helped now.
3: Medical machines feed a black slurry of fluids down an IV drip.
???: This whole operation, such a mess…
4: The figure is revealed. It is the large, bulky, mutated remnant of Hedgeworth’s true insect form, now bloated and twisted by strains of the Black Mass. Eyes and mouths and thorns poke out from rows of chitinous plate. Many medical machines are hooked up to the body.
Hedgeworth: But… a serious outbreak was prevented either way…
Things might calm down now, without the Mass on the moon influencing them, but… I suspect keeping this secret hidden will be impossible…

Big bad final boss-form!
I do not remember Hedgeworth heck, is there a last appearance I can check as a reminder?
Check the chapters “Beast of Spearmont Pass”, “Seekers in the Dark” both parts, and “This Ruined, Forsaken Rock” for the majority of Hedgeworth’s story so far. I think he popped up a few other places, but that’ll get ye the main storyline for the most part.