this isn't pervposting it's just a random thought. and i think agar agar cookie is probably a child? i recall pomegranate cookie called her that so i don't ever wanna include her in the pervposting. (NOTE: i'm still rating this as M though simply because i don't want minors on this acc)
but i was remembering how lord of flame/lord of ash are less of an actual "self actualized/'corrupted'" thing like other legendary are (e.g. blissful full moon & alluring crescent moon) but instead more of power imbalance. there was an ovenbreak event when the costumes were added and his story sprites would become them if he got to certain areas (both have him in pain). so lord of ash happens because he's EEZING !! (he can also go ash because sea fairy cookie can put him out implied in his relationship chart entry for her but that's not relevant)
which is why it caught my attention so much in the intro scene and in story cutscene when agar agar cookie is freezing him solid and stuff. and not even just that but the dragon's valley is cooling AGAIN (it was like this in ovenbreak too) so like. devsis you have a really cool costume you can add. i know that his kingdom exclusive costume is part of the lore but it also had me thinking of my own idea. what if agar agar cookie does turn him into lord of ash and he realizes he needs to retreat to plan his next move. and even though he's weak he can still power through. (i haven't fully finished this story yet cuz she keeps beating my ass in her boss fight) but i think it's a cool opportunity they (sadly) didn't think of.
maybe when they finally make dark enchantress cookie playable they'll add the "corrupt" legendary costumes but who knows... i say corrupt in quotes because lord of ash and dread trident of the abyss aren't evil, just active suicide risk and nothing burger pretending to have depth respectively.