Cultivation
Cultivation is you refining aura and evolving which increases lifespan and strength it's split into tiers and realms.
It starts at tier 0 which is mortal then tier 1-3 which is basically cannon fodder. Tier 4-6 which is for nobles in a small kingdom/territories and tier 7-9 which could be the king/queen of a small kingdom. At tier 9 you can fly without the wind element
After the 9 tiers is the realms each realm is split into nine floors (which are basically small realms in cultivation novels) is Transcendence which is where you temper and transform your body into element(s) of your choice the more elements you choose the stronger you'll be in the future and it be easier for you to advance in cultivation later on.
However the more elements you choose the longer it takes to cultivate and if your not talented enough in a element it may takes decades. Also one you chosen the element(s) you cannot change so you must cultivate or die.
After you break through transcendence you experience a tribulation and from now on at each big realm breakthrough there is a tribulation.
After transcendence is the Emperor realm which allows you to rip through space with pure strength and teleport however it is not as efficient as someone with the space element
After the emperor realm it's the True immortal realm this realm is just a strength increase nothing special
After is the Dao realm Where you cultivate your understanding of elements after you understand laws your elements transform into laws which are stronger than normal elements. You need good comprehension for this and once again the more laws you understand the stronger you are later on.
After you got the saint realm where you fuse your laws into your tempered body creating a body of law.
Tribulation realm you go through nine tribulations at each small realm. This is the highest so far no one has passed this realm due to the laws of the world changing
The peak is eternal realm where you are immortal for as long as the world exists
Obviously the MC breaks through that and will be in the Nihility realm he is nothing and everything, omnipotent
Cultivation techniques and spells, equipment and treasures (medicine)
All of these things are in the same tiers the tiers are
Mortal (tier 1-9)
Transcendent
Monarch (Emperor)
Immortal
Law (Dao)
Saint
Triubulation
Heavenly (eternal)
The higher the tier the higher cultivation or comprehension needed to use the treasure/technique/equipment
Spells are ways of using aura and can be learnt by anyone some spells have different elements needed you can also make your own spells. Simple things like creating a weapon out of an element do not require specific spells as it falls in the category of aura manipulation
A lot of physiques and bloodlines have a specific cultivation technique an are normally imprinted into the mind of the owner once they are ready to cultivate so around age 5 some are ready earlier or later depends on comprehension.