There really isn't another way to explain the Cosmos. Everything that can be imagined and/or is alive is part of it, or will be part of it, or was part of it. There are some cultures that believe that the Cosmos has a conscience, that it's very much alive and it's the most important deity to exist. These same cultures believe that the Cosmos does not speak to mortals the same way other deities do because its energy is being spent in destroying and creating lives, worlds, galaxies and dimensions. This belief certainly fits well with the fact that the Cosmos has its own set of rules and regulations in order to keep itself balanced at all times, but no concrete evidence was ever found. Nonetheless, one must keep the consciousness of the Cosmos in mind at all times.
There are two major dimensions that constitute the plane of existence: the immortal plane and the mortal plane. These names are self-explanatory, however there's need for them to be explained further. The immortal plane, as the name suggests, is home to all immortal beings of the Cosmos, i.e. deities, constellations and some demigods. There are many other pocket dimensions inside of the immortal plane, many of which are home to minor gods or constellations. The Regents also reside in the Immortal plane, on a dimension of their own. Likewise, the mortal plane is home for all mortal beings of the universe, like humans or dragons. Pocket dimensions are rarely seen in this plane; alternative dimensions are more common.
The Regents are the highest authority in the immortal plane, right after the Cosmos itself. They were created by the Cosmos after the dawn of creation to fulfill the duty of protectors of life. Regents were meant to enforce the cosmic laws and be the representatives of their creator. Regents do have a physical appearance, though it was created out of their need to communicate with mortals throughout the years. Regents only have one limitation towards they magic: one cannot harm a sibling by using only his own magical power. These are the most powerful entities of all the Cosmos. It's also important to note that these beings can create constellations and minor gods at their own will, but cannot normally create mortal life from scratch.
Originally, they were four: Dragon, Wolf, Snake and Cat. All created from the same stellar dust, all created at the same time. It's safe to say that they were pretty close once, when they were still too young and naïve and the Cosmos was just a fraction of its current size and grace. In those young ages, the Regents visited the mortal plane frequently and became gods of dozens of civilizations. However, as they grew older and mingled with mortal societies, their innocence and purity started to fade, being corrupted and replaced by innumerous sins and darkness.
The first sign of corruption also sealed the fate of the deities. The Cat, who had been busy spreading her beliefs and creations across the Cosmos, returned to her home dimension, exhausted and looking for a million years nap. What she found, however, left her distraught. She saw right through the masks her siblings were wearing. She saw the Snake's pride and the Wolf's apathy. But, above all else, she saw the Dragon's envy and greed. Oh, and his wrath. She saw it as a burning flame, destroying everything in its path, mercilessly. There was no denying that she was scared and desperate.
She discovered that day that the Dragon wasn't as docile as he seemed. A vision flashed in her mind, of a vicious plot that would threaten the Cosmos as a whole. The Dragon had to be stopped before it became too late. The Cat tried to warn both Snake and Wolf, but they did not heed her words. Worse, they called forth the Dragon so he could stand witness to what his sister spoke. Swiftly, the Dragon turned the situation against the Cat, claiming that she was the one filled with greed and envy and that the proof was staring them at their faces. She had already started her plot to overthrown her siblings: with her conspiracy theories, she sought to create distrust and anger between the brothers, which would eventually turn into a war and, as her siblings fought each other until the end of their existences, she would claim the throne alone as Regent.
The Dragon's plan worked and, together, the three Regents banished the Cat from the immortal realm, soon to be forgotten for eternity as her essence withered. She had been prepared, however, and created her own legion of loyal felines who would always pledge their very existence to her. Throughout the ages they would carry on her story, her legacy and, one day, she would reclaim her rightful place as one of the four Regents of the Cosmos.
Millennia passed and the subject was never brought up again. Life seemed to follow its natural course in peace, with little to no disturbance from the affairs of the immortal plane. New minor deities were created by the Regents to attend to more specific matters between mortal, like a god for the harvest and a god for the rains. However, tensions began to rise among the civilizations that still worshipped the Regents, especially the Snake and the Wolf. The Snake and her followers defended the idea that death ruled the Cosmos. Life had been created to serve death and, inevitable, everything that lived would die one day. The Wolf and his followers, on the other hand, defended the idea that life ruled the Cosmos. After all, death was only a means for new life to sprout.
The war did not begin between Regents. It began on a small planet when two different societies clashed together. The desperate prayers caught the attention of the Regents who descended to the mortal plane, shocked by all the violence. The Wolf, being the strategist, discussed the situation with the Snake. He pointed out that if she decided to drop her claims about life and death there would be no more conflict. The Snake, too proud to give up, disagreed, stating that the Wolf should be the one to drop the claims and stop all the fighting. The Wolf, angry with his sister's stubbornness, decided not to go through with it and officially declared war against her.
The event would be known as the cosmic wars, the single greatest conflict of cosmic history. Thousands of planets and species became involved. Constellations were created day and night and demigods were brought to existence almost daily. The Regents did not fight one on one; it would be pointless as there's only so much harm one can do to the other alone. Both immortals and mortals were tired and angry at their gods.
The Dragon saw the war as an opportunity. He abstained from supporting one of his siblings, but created and trained his own army "just in case". When both sides of the war became angered with the Regents, the Dragon stepped in, saying that his siblings were wrong and have always been wrong. He stated that life and death existed in balance and that one could not exist without the other and, together, they ruled the Cosmos. He instantly sent his army into battle.
Many warriors and mages deserted the war, seeking a new and peaceful life among mortals far away from the conflict. For the longest time they were considered traitors, only receiving pardons recently. Both the Snake's and the Wolf's forces were becoming smaller and weaker by the day. Seeing the distress in his siblings' eyes, the Dragon decided to cut a deal with one of them. He said he would join forces and banish the other, to finish the war once and for all. In truth, the Dragon planned a trap in which he led both Snake and Wolf into. By using the energies of the Snake and Wolf combined with his own he was able to create a pocket dimension and imprison his siblings, who would be too tired to break free for millenniums to come.
The war was given as finished and a new era of peace began. Or, at least, it was supposed to. The Dragon became a tyrant, being cruel to even his own children. He brought upon the immortals an age of oppression. Mortals were rarely guided by gods anymore. There were, however, some improvements on the Dragon's reign as single Regent, like the creation of the position of cosmic scribe and warden of time and space. The scribe would keep record of the Cosmos and protect its integrity by classifying and managing the information recorded, careful not to allow any dark entity to gaze into the secrets of the Cosmos. The warden would protect time and space on the battlefront; a warlord who would save the very existence of the Cosmos if it was ever threatened.
As time passed, Snake and Wolf were able to reach out to the mortal plane and called their children to aid their escape. Many refused to take the call, too busy to care about gods. It took a long time but the two Regents gathered enough forces to break the barrier that kept them locked inside the pocket dimension they were in. As soon as they released themselves the Dragon declared war on them, claiming they were traitors – and enemies of the Cosmos. The Dragon's tyranny was the cause of his downfall. Deities, constellations and demigods all united against him. His own children turned on him. He was soon defeated and his essence withered.
But a Regent cannot disappear like that. His soul was transformed, mutated. He was soon born into existence again. This time, though, he was different. Coded as female, the new Dragon was extremely naïve and innocent. She became instantly scared of her own brother and sister and tried to hide away between nebulae. With time, she learned to trust them and listened to their stories. The three Regents were deeply regretful of their actions and vowed to do better for the Cosmos and its creations. They slowly began to treat the deep wounds left by the cosmic war.
Minor gods are ranked just below the Regents. They do not possess any physical body, but do possess avatars (magical projections on the mortal plane used to create a physical appearance to its caster or to hide someone's true physical body), specially on the mortal plane. They were created either by the Regents or by the mortal's desperate need for a deity. Religion is, after all, an important aspect on mortal life – even if those mortals do not believe in any. Minor gods possess a few limitations to their powers, the most noticeable being that they cannot control the natural magic that flows through the Cosmos and must instead harvest it, normally from prayers and sacrifices made by the mortals that worship them.
They weren't so popular back when the Regents were in harmony with each other. After the cosmic war, specially, the need for other deities increased and dozens of new gods were created each day. It's safe to assume that, during the war, these entities could not have been created by the Regents, who were too busy focused on their war efforts to pay attention to the mortal plane. It's speculated that minor gods can "create themselves" or, rather, that the collective need for a deity sparks the creation of a new entity. There's still much need to study this process.
Minor gods are usually responsible for a limited amount of "tasks" or elements on the mortal plane, on a specific culture and society. They cannot meddle with other deities' responsibilities, though they can interfere physically on these entities' worlds and make the job harder. Some societies are used to calling these interfering gods "the devil" or other similar names, always attributing all wrongdoings to this particular entity. You must not confuse, however, the singular devil with the presence of demons in mortal worlds.
Just like the Regents, minor gods are capable of creating constellations, though in a more limited manner due to these entities' own limitations. When one is created it's usually to run and manage small tasks that the own gods cannot be bothered with. Another common practice among minor deities is the training of apprentices, who are to be their heirs. Minor gods cannot die per se, but they can become out of touch with reality, or their essence may wither with time. It's noticeable, though, that minor gods can imprison each other on pocket dimensions that are too far away for the harvesting of magical energy, causing the imprisoned entity to wither and fade away.
Heirs are normally minor gods who lost their regency of the mortal world or were created specifically for apprenticeship. The latter is more complicated as it requires the consent of the Regents, since they are the ones creating this minor god. It takes noticeably longer, but it's a more secure way of obtaining a heir.
Minor deities can become easily corrupted, be it by their own sins and sentiments or by the interaction with Caotic energy (I'll come to that shortly). These corrupted entities are cast away from the godly society to wither and fade away alone, in suffering. It's important to notice that this may not be the fate of those who are corrupted by Caos, as they become Fallens and may be able to run to the mortal realm, where they'll become highly unstable parasitic creatures who feed on souls.
As mentioned, gods do possess a society. They're all ranked by their age and the senior gods are considered their wise leaders, being looked up to by every other god. It's a great honor, especially considering that not many gods make it to old age (millenniums, in this case). Younger gods are seem as unexperienced and are often picked on by older gods.