>>96834201
Like the others said, the Nurarihyon is the 'leader' of the Yokai and Idea World forces. The HLA likely knows the most about him in character since they're aligned with him. It's unlikely he'd reveal himself though.
Did a cursory check with the completed writefags, and so far his 100 demons include:
>Warlord Kakito (Tomaki Sheets)
Likely high ranking in the Nurarihyon's forces, but I don't think we have a confirmed number on him. He leads an army of Yokai in the mountains and Idea World, but was defeated by Tomaki and had his tooth stolen. A physical powerhouse, but weakened until he gets his tooth back from Tomaki. We know the most about him in terms of abilities because he actually has a sheet.
>Baku (An Offer He Couldn't Refuse)
42nd of the 100 Demons. Described as humanoid and dressed in a Jester's motley, and pic related was the FC used. Powers are nebulous, but likely related to fire ('Wickerman our ass') and dreams. Seems to respect the Warlord Kakito, dislikes the other named Yokai.
>Fushihara (Love and the Russian Winter Part 4.5 + Epilogue)
4th of the 100 Demons. Arguably the strongest character in the MP thus far, even though his only 'appearance' was a near death experience from Alyona. Described as a skeleton in robes, and says a buddhist prayer when he tries to strangle Alyona. I'm imagining Daisoujou from the SMT games, but he's probably scarier than that.
>Omukade, Ogama (An Offer He Couldn't Refuse)
Mentioned by the Baku, though their ranks aren't given. We know nothing about them in the MP, but in real life the Omukade is a massive Centipede while an Ogama is a Toad that lives a really long time and grows to human (or larger) sizes. Ogama is mentioned in Rin's Relationship Chart, so he might have recruited her to the demon's side like Baku recruited Kenji.
I'm excited to see the rest of the 100 - doubt we'll get all of them, but there's enough 'free spots' that anons don't need to feel constrained in making up a bunch.