First off, there are now more celestial beings that just StarClan. There are Gods, Demigods, Star-Spirits, Constellations, Ghosts, and Fog-Spirits.
Gods are the most powerful of the beings, and they have little to no connection with the mortal world. They each represent a metaphysical concept, and are known as the 'icon' of the concept, such as Nebula beung the icon of Creation or Event Horizon being the icon of Consumption.
Demigods are much less powerful than Gods and are based on celestial bodies. They represent physical or tangible concepts such as War, the Sky, or Cold, and are known as the 'essence' of that thing such as Pluto being the essence of Ice or Jupiter being the essence of Wind.
Constellations arecbot actually 'real' beings in any sense but are instead the subjects of stories. Many constellations do have an effect on the intangible world, but most often they are just the cause of stories. They are the same constellations as we have in our world, but with different stories.
Star-Spirits are the spirits of cats who led good lives and followed the Warrior Code. as a reward, they become stars in the sky, able to look down upon their descendants. Sometimes a non-Clan cat who lives a noble life can be brought to StarClan, but this is rare.
Fog-Spirits are the spirits of cats who did horrible things in life. It is condiered the worst punishment to be sent to The Fog, an endless plane of low-lying fog with no food, not other cats, and no sky. To be in The Fog is to be completely cut off from everything else, much like a sensory deprivation tank. It is the equivalent to the Dark Forest.
Ghosts are the spirits of cats that lived neither good nor bad lives. They simply are. Most of them are Loners, Rogues, and Kittypets. Ghosts are often reincarnated. They wander the physical world and can be seen and interacted with by those who have ghost-sight.
Star-Spirits are not that powerful on their own. It is very difficult for them to visit a living cat, even in dreams.
Some things that can make it easier are if they had a close relationship with the cat in life, if they are a particularly powerful spirit(such as a notable leader), or if they have the help of a God.
Star-Spirits can send Omens fairly easily. They are capable of minorly manipulating the material world to send messages.
Leaders, Deputies, and Healers are the most likely to recieve visions or omen since they are considered high ranking members of the clan.
Healers do not have a special connection to StarClan, however they tend to be more knowledgable about it along with Mediators, Queens, and Elders.
After than is Healer Apprentices, Mediators/Med. Apprentices, Elders, Permaqueens/Queen Apprentices, and Senior Warriors, recieving visipns occasionally.
After them are Warriors and Apprentices, they do not recieve visions often but it does happen sometimes.
Kits almost never recieve visions or omens, though it has happened before.
Fog-Spirits cannot visit the material world or influence it in any way, nor can they visit any living cats in dreams.
Living cats can sometimes be sent to the fog in a dream, typically thse who have a strong connection with the fog. This is the only way a Fog-Spirit can interact with a living cat.
Gods rarely, if ever speak to mortal cats. They will either send a Star-Spirit or just not communicate with them.
They are often percieved as strange. They speak in stuttering voices, they have long pauses between words or sentences, and they stare eerily as if they are somewhere else.
This is because Gods often have their attention elsewhere, often in hundereds of places. If a God speaks to you clearly, it is very serious.
It is incredibly taboo to name a kit after a God. Excluding Dark and Horizon, which can be used as names, it is seen as incredibly disrespectful to use any of the Gods' names for a mortal cat.
Supernova is the icon of Destruction. Despite their domain, they are rarely a violent entity. Instead, their purpose is to help the Star-Spirits who have been among the stars for too long to move on and to fade away.
Nebula is the twin of Supernova and the icon of Creation. They are tasked with creating stars for the new spirits when they ascend to the skies. It is said that they take special care with the spirits of kits, leading to them having a flurry of 'baby stars' floating in their tail-cloud.
Cosmic is the icon of Togetherness. They embody the crucial spirit of teamwork and community within a Clan, and pull uts members together.
Event Horizon is the icon of Consumption. They were created by Supernova by accident, and have been a bane on the other Gods since. They are fundamentally different from their 'parent'. While the be destroyed is to be changed---irrevocably and forever, but not erased--- to be consumed is the be removed entirely. They reside in The Fog. They speak clearly unlike the other gods, as they do not split their attention.
Empty is the icon of Nothingness. Their existence in itself is debatable, since to be nonexistence you must not exist. SImply put, they are a paradox and it is unknown if they are real or just a creation of stories.
Cumulus is the icon of the Unknowable. They are constantly shifting, changing, and morphing into other shapes, one second resembling one thing, then the next something else.
Darkness is the icon of Guidance. They are known as a helper from the shadows, never seen but rather felt. They offer assistance to those in need who cannot get it from the material world.
Unlike Gods, Demigods embody tangible or material concepts.
They have much more communication with Star-Spirits, but equally as little with the mortal world.
Not all Demigods are know to the clans. Known demigods include the 7 planets excluding Earth, Pluto, Ceres, Luna(Moon), Titan, and Europa. There is a corresponding demigod for every celestial body, though only those listed here are known.
Unlike Gods, it is not taboo to name a kit after a Demigod.