Ordinemon's Guide to the Omniverse
The Dreamlands
The Dreamlands is the nexus of the omniverse. While there are many alternate universes in the omniverse, there is only one Dreamlands, shared by and connecting all the universes. Most beings can only reach the Dreamlands in their dreams, but a few (primarily tesseracts) have the power to come and go at will. Some other beings make their home in the Dreamlands and do not exist in any physical universe.
Notable Inhabitants
✷ Luke and Jan Valentine are vampire brothers who were killed in a physical universe but somehow found themselves spending the afterlife in a bizarre, cartoonish place of which they are the only inhabitants. The area is somehow connected to the Dreamlands (possibly a pocket dimension of it), and the brothers can enter the Dreamlands for short periods of time. Luke tends to be the one to do this, while Jan prefers to stay at what they've come to accept as their home. They are unable to remain outside their world for long, finding themselves popped back into it when their time's up.
✷ Nyarlathotep is a tesseract chaos deity, messenger of the eldritch gods and son of Azathoth, one of seven tesseracts who were the first beings created. He moves throughout and outside the omniverse as he pleases, but he has taken up residence in a palace of black glass in Kadath, at the north pole of the Dreamlands.
✷ Hastur, called "The King in Yellow," is a tesseract, the cousin and high priest of Nyarlathotep. He divides his time between his own kingdom of Carcosa and the temple to Nyarlathotep in the Dreamlands, located in a place called Sarkomand on the Plateau of Leng, in the north near Kadath.
✷ Randolph Carter is a human man who dared to defy Nyarlathotep - and won. He has learned how to travel among the universes at will but now spends most of his time in the Dreamlands. He is a dear friend of Kuranes, the King of Serannian.
Serannian
Serannian is an idyllic city in the Dreamlands located on a island floating in the sky above the Cerenarian Sea. It is one of two cities dreamed into existence by Kuranes, a human who gave up his life in a physical universe to dwell exclusively in the Dreamlands. Serannian was the site of a great battle with Nyarlathotep, who resented Kuranes's abilities as a dreamer and the happiness of Serannian's citizens. Nyarlathotep succeeded in razing Serannian, but the small group of beings who opposed him called upon all the dreamers in the omniverse for aid. They dreamed Serannian back into existence, leading Nyarlathotep to realize that his cause was hopeless and retreat. Many sentient airships and balloons live in Serannian, and it is where the souls of balloons go when they pop.
Notable Inhabitants
✷ Kuranes is the creator and king of Serannian who divides his time between it and Celephaïs, the other city he created.
✷ Emily is the first being ever to exist in the omniverse, one of the original seven tesseracts. She opposed Nyarlathotep in the Dream War and gathered the group of beings who fought him and ultimately caused Serannian to be recreated. She is friends with Kuranes and remains in Serannian, although she keeps a close eye on Nyarlathotep.
✷ Poof the Drifblim is a key figure in Serannian's lore. A balloon Pokémon, he was brought to the Dreamlands by Emily to oppose Nyarlathotep, and Poof led the Just Balloons in their fight against him. Poof was responsible for calling upon the dreamers of the omniverse to restore Serannian.
✷ Szardiis
✷ Blimpmon: Kyzer the Blimpmon. One of the Just Balloons whom Emily brought from one version of the Digital World. He now helps guard the city.
✷ Aerostat: He was a barrage balloon existing in the "real" world. When he was destroyed during WWII, he came to the afterlife in Serannian. He guards the city alongside Kyzer.
✷ Prospekt: a Drifloon who came from one of the Pokemon universes to join the Just Balloons.
✷ Bart the Black Blim
✷ Popped: a balloon who popped in one of the physical universes and came to the afterlife in Serannian.
Nonexistence
The space between the universes, sometimes called "Nonexistence" or "todash space," is inhabited by monsters and other bizarre entities. It is freely traversable by tesseracts, but most beings can only find their way there by accident and can easily be lost there forever. Throughout the physical universes are "thin spots" or "thinnies" where the universes' barriers are weak, and their inhabitants may be able to cross into another universe or into Nonexistence.
Notable Inhabitants
✷ Jowday: the embodiment of an "extreme negative force" who existed Outside, beyond even Azathoth. A combination of the Trinity Test and the casting of an occult ritual called the Babalon Working forced her into a physical universe (that of Twin Peaks), in a physical form.
The Dark Ocean
The Dark Ocean is the primordial sea from which all realities and universes emerge. It lies at the bottom of Nonexistence but also extends into the Digital World.
Notable Inhabitants
✷ Ordinemon
✷ Ysthli is an eldritch entity who takes the physical form of a massive blue oyster with a tri-lobed eyeball as her "pearl." She is worshipped by a cult of decapids, anthropomorphic squid, on the ocean planet of Moana orbiting the star Rigel.
Outside the Omniverse
Outside the Omniverse is the vast expanse that lies beyond the physical universes and the Dreamlands. It is where Azathoth dwells with his court, and is also the home of some other races of entities who lack a physical form as we in the omniverse know it.
Notable Inhabitants
✷ Tak is an eldritch entity who dwells in Nonexistence, possibly but not necessarily a tesseract. He cannot take a physical form, but he has tried multiple times to exist in the physical universes by using other organisms as host bodies. He has been unsuccessful thus far and is currently trapped between alternate physical universes.
✷ EASY: a tesseract working for someone (possibly Nyarlathotep) from Outside. She takes beings from various universes who are near death and places them in other universes. She lives and works in a hallway on the Outside lined doors, each leading to another universe. She takes a humanoid form in order not to break the minds of the humans she deals with.
✷ S'ngac is, to the perception of those from the physical omniverse, a violet-colored cloud who has devoted her long existence to study and learning. She is fascinated by physical beings and is friends with Kuranes and Randolph Carter. She has aided in their struggles against Nyarlathotep.
Key Figures in Physical Universes
✷ Bob-omb: Sparky the Bob-omb, who exists in multiple Super Mario universes. This particular version of him lives in a self-contained time loop universe.
✷ Floon: Celeste the Drifloon. She lives in the physical universe from which Poof originated (the Pokemon Diamond/Pearl/Platinum game universe).
✷ Balloon
• Louder• Drifloon
• Al Cody
• Llewyn
• Togemon
• Herne
• Valtiel
• DJ - once ensnared by Ysthli
• Tivan - Elder, immortal, ancient in his universe (the mcu one). Aware of other universes.
• Sweets
• Frio
• Rubel
Other pets, probably won't be included
• Topper
• Smiley
• Frowny
• Horsedreamer