Core Substance

First off; the substance that humans actually manipulate.

I will call it subs- as in substance... for now.(maybe permanently, idk)

Subs are normally invisible to the eye, but there are methods to investigate them, and if enough of the same subs type gather it will give off a weak aura noticeable by people cultivating that or a similar subs. Subs are a phenomenon that has no actual weight, but consists of individual substances that attach to atoms and give them different attributes or modify their existing attributes.

Subs can evolve into world subs of different kinds(concentrated materials), world subs are usually concentrated into an item using a complex and very taxing method(that can easily fail if done wrong, if it fails the backlash can injure the Master in different ways depending on different factors), in order to stimulate the effects the World Master wants from his surroundings in an easier manner - these items are referred to as World Items, and are usually very rare; once it reaches a certain level of power it will have gathered so many subs in a specific pattern that it becomes impossible to make another at the same or higher powerlevel with the same effects, without using the original world item as a material to make the new one, or destroying the original one before making the new one.

There is no end to the mystical effects achievable through different World Items, just limits to the level of the effect according to the level of the world item. And just like there is no end to the effects, if the effect is overly mystical the cost is also not orthodox like other World Items, it might consume things like lifespan, cultivation, air, life (as in multiple lives, the Master, several Masters or just Several mortal lives.), water, time, maybe even affecting your personality, taking away a specific kind of emotion or other, or feeding off of that emotion(not completely consuming it but eating some of it)- or you might not even notice any cost for exciting the World Item, but there is always a cost, no matter what.

So once world items reach a certain level they become unique, though the same effect can be achieved through other world items used in a complex combo, but this method undoubtedly consumes more. Once Masters reach the same level they are referred to as Master Magi.

The World Items of this level are usually referred to as World Spirits or just Spirits normally, once they reach this level they will develop a small amount of intelligence, this intelligence is part of why wild Spirits are hard to catch, and why Bound Spirits actively help their master to perform combos or cultivate. World Items that are imprinted with the Masters will but not bound is controlled by their Masters will , once they become spirits they will follow the Masters will, but wont actively help or hinder the master.

World Items can exist in the wild or have a Masters will imprinted on them.

Masters can also create a life bond with a World Item, which lends a lot of resilience to it if the upgrade of it fails or similar things happen,it also adds more power to the World Item when used by the Bound Master. The Bound Master gains more subs within the Bound Items category when upgrading cultivation base level(and generally when getting stronger within the specific category) and by passing the tribulation(especially during the tribulation!the tribulation is a moments crisis for a future of wealth.)

The bound item cannot be changed without experiencing fierce backlash according to the type of World Item; the bound World Item will break and the backlash is usually fatal if experienced recklessly, and if contained it might still jeopardize the cultivation of the Master, this of course also depends on the World Item itself.

Generally the Bound Item of a master should be at the same level of the master, if it is higher the cost of urging it increases a lot(usually, exceptions to the rule make the world more vivid and magical, if i write «usually» in parenthesis later on this is what i mean.), if it is lower, the effect is just that; as low as its' level plus the modifyer that is the inherent subs in the cultivator, and therefore has a reduced use for the cultivator.

To conclude, subs is the manipulated substance, it is manipulated through Items and Spirits(capitalized first letter incase the sentences' context might confuse the reader), Masters and Master Magi alike have to watch out for three aspects when it comes to these items and spirits;

How to use them(Combo moves, formations, lasting effects, and so on.)

The cost of using them(you have to «feed» them every now and then so it doesen't degrade over time, «feeding» them is not straight forward at all, it costs to excite them, and there are costs in imprinting your will on them.)

And how to make and upgrade them.(very complex and tiring process in the first place, which will fail and backlash if done wrong, and sometimes fail for seemingly no particular reason at all. That is if you can even get a recipe, if you can't get a recipe you have to make one; something that is both laborious, hard, and expensive. At the end of it all, even just making it can become pretty expensive depending on the recipe and level of it.)