The universe of my stories has a set of primary rules that are shared between all worlds, in addition to variable rules that may differentiate from dimension to dimension (for example, the world of Ezera is a lot more suitable for magic than the world depicted in The Grinning Woman).
Reproduction. New beings come into the world through the process called the shining: when an individual or, more commonly, a couple, or even the world itself, shines into the primary hollow or infinite darkness expressing the conjoined wish to extend one’s lineage. This wish can be granted or not by the Greater Will. New beings can also be created directly by the Great Eye of Creation or the Ancients with the Power of Origination.
Food and water are not necessary for survival. While abstaining from all foods might cause a grave sense of exhaustion, it can be overcome, and depending on the world, it might take years to decades, or even centuries, for such exhaustion to cause the death of an individual. Additionally, the organisms of the beings in the universe are built in such a way that the absorption of the food is total, and there’s no waste product, apart from when something poisonous or inedible is ingested. In that case, such an object is removed from the body through retching.
The shining can not be forced onto anyone. When two individuals shine together, they temporarily become one, sharing all their memories and desires, creating a bond that can only be broken by complete eradication. This process can not be forced onto anyone, and the shining always happens as an expression of an individual’s free will.
There is no concept of unanswered love. While a form of infatuation and a feeling of possessiveness can exist, it can never grow into anything more substantial if it is not answered, except in rare cases when the feeling of love is temporarily fabricated by the charm magic, and even then, it only works if the cursed individual is not currently in love with anyone else. Thus, concepts such as love triangles, infidelity, or falling out of love are non-existent (except for one of the individual’s total demise).
Primary rules are final, and all must abide by them, even the Ancients and the Great Eye of Creation. While they technically can be overridden by the Primary Hollow in the way of anomalies, these rules are the corner-stones of the universe itself, and it is not in the nature of the void to seek to break them.