With Kraken being inspired by Cthulhu, I thought a monster based on Nyarlethotep would be cool.
My proposed monster name would be "Messenger" since Nyarlethotep is the Messenger of the "Outer Gods".
He is also a prolific shapeshifter, so each of his 3 stages would look different as opposed to being bigger versions of the same creature.
Stage 1: The Black Pharaoh (Basically a humanoid with skin as black as shadow)
Stage 2: Haunter of the Dark (A Dragon-like monster form)
Stage 3: The Crawling Chaos (Nyarlethotep's true form?)
The unique aspect of this monster is that his play-style would change depending on which stage he was in.
Stage 1: Messenger is the size of a normal hunter. His traversal is a short-range omnidirectional teleport. Rather than "feed" with his mouth he siphons the life energy of wildlife into his hands to increase his strength. He has an incredibly small hit-box compared to his other forms, but is especially "squishy". He must rely on his stealth abilities to avoid the hunters. In lieu of a jetpack, Messenger can chain his teleports together.
Stage 2: Messenger can now fly like Kraken by expending a traversal change, but can teleport while in the air, and is now as big as most other stage 2 Monsters. He now "feeds" like normal, by eating the wildlife.
Stage 3: Messenger is now a massive lumbering monster about the height of Behemoth, or slightly taller, but much thinner. His traversal is now a leap similar to Goliath/Meteor Goliath
Here are Messenger's abilities, which change slightly depending on stage.
Ability 1: Shroud
Messenger becomes a shadow of living darkness. He can be tracked visually in well-lit areas, but inside dark areas he is effectively invisible. The first melee attack against a hunter from the shadows does additional damage, and if the attack is a sneak attack does even more damage (maybe instant KO, but that may be OP). Once messenger attacks, he is revealed, but he may use traversal abilities without breaking stealth.
Ability 2: Decay
Messenger attacks a target with a projectile of dark energy that ages and slow the target. While the ability is being channeled against a target they are slowed, and they take damage over time.
Ability 3: Madness
Messenger opens a portal to the Outer Gods. Those within the radius of the portal are driven mad and flee from the direction of the portal while taking damage over time.
Ability 4: Dark Pact
Messenger can resurrect an in-capped hunter to fight for him for a limited time. The possessed hunter slowly loses HP even if they are not attacked, and effectively become "bots" fighting against their fellow hunters on behalf of the monster until they are in-capped again, at which point they can be resurrected by their teammates as allies. The strength of the ability determines what percentage of the hunter's starting HP the possessed hunter starts with.
Messenger is a Monster that specializes in disruption. He is the Crawling Chaos after all.