#nihilix

Come to think of it, sadly not a single one is heavily bird-inspired.

Nihilix was the first demon to exist in the DeepC Multiverse who birthed almost, if not, all the first demons of the Inferno. As mentioned before, Nihilix is a colossal cube made of black holes and void that looks like something Stephen Gammell and M.C. Escher teamed up to design, but they can take on all kinds of appearances that you dread. 

Another thing they do is they are able to seize entire worlds under their control, imprisoning them from the rest of the Multiverse and entrapping said worlds in apathy and bleakness (Represented through the worlds surrounded by wisps of dark grey). 

The inside of them is a constantly expanding labyrinth of shrouded darkness that goes in various directions that one can get lost in for eternity. 

I don’t know how exactly to describe their other powers, but they’d definitely be something you’d find in some ultimate RPG boss.

Glad you asked about those 3 together since they are supposed to be grouped as a trio.

They are the Infernal Trinity and they are the 3 most powerful Demon Lords.

Maelstra - A gas giant planet (Think like Saturn) with a permanently scowling face. They exist between planes of reality between outer space and the Inferno. Maelstra is incredibly apathetic to their servants and any denizens living on them. They have a pretty good amount of control over their planetary functions however they want (Orbiting, where winds go, core temperature, climate level, gravitational pull, etc), which isn’t so good for anything living on Maelstra. Maelstra’s personality can be best described as bombastic, apathetic (Unless it’s concerning their ego), and condescending. Maelstra is somewhat resentful of their demotion to Demon Lord #3 from Bellzog.

Bellzog - A demon that resembles a cross between a Ray Harryhausen Cyclops and a wingless dragon. He is the 2nd most powerful Demon Lord thanks to reality-warping and the ability to grant wishes (Although the likelihood of them coming true WILL vary, and even then, they easily backfire), and he also has the powers of fire-breathing and great physical strength to help him. He started out as a lesser demon alongside his sibling (No idea if brother, sister, etc), Golbog, until he managed to acquire his reality-warping abilities (Not sure HOW it happened yet), in which he quickly climbed up to the top. However, when he attempted to fight Nihilix, Nihilix made short work of him. Bellzog’s personality is prideful, trolling, yet fairly affable.

Nihilix is Demon Lord #1 in that they are the most powerful of them and controlling the most territories of the Inferno (DeepC Multiverse equivalent of Hell) as well as some areas of the DeepC Multiverse. Their appearance is that of a humongous cube made of void (Think like a black hole shaped like a cube) and inside of them is a constantly expanding labyrinth of shrouded darkness that goes in various directions (Imagine it looking like a cross between MC Escher and Stephen Gammell).