A significant antagonist in my trilogy is an omnicidal alien by the name of Loki, whose characterisation borrows from Griffith, Keizer Ghidorah, Randall Flagg, Saruman and Hastur. Throughout the series, Loki takes forms called “Masks” to interact with disciples or masquerade as various species, per his epithet “the Billion-Faced Beast”. One “Mask” he uses is that of an priest named Father Nguyen to provide false emotional and spiritual support to the deuteragonist implied to be Jeanne d’Arc. Loki later tells the deuteragonist that he killed the real Nguyen to destroy her sanity (who suffers from Major Depressive Disorder, thanks to struggling to conform to modern society, everyone she knows being dead and having no human contact for over six centuries).
Another Mask used by Loki is a person who leads an anarcho-communist and anti-fascist group. Loki uses this Mask to have his sociopathic, authority-hating followers commit political violence against and kidnap innocent civilians to give the Degenerates (humans parasitised by prehistoric pentastomids styling themselves after nomadic Indo-Iranian cultures and resembling a certain endoparasitic extraterrestrial) with hosts.
I have scattered several hints throughout the series about Loki’s identity by having him only assume Masks between 10 (his true form’s height) or 5 feet tall and makes heavy footfalls when walking. Another major clue is that he always retains his scarred lips, venom burns, falconic eyes and high body temperature in every Mask. However, I still don’t think this enough, and it all comes across as very heavy-handed.
How, then, can I hint Loki’s identity without being unsubtle?