This is a xuanhuan and so it is a mix of high eastern fantasy and western fantasy. Characters cultivate magically or physically in order to achieve immortality. They are born with a level of proficiency in certain types of magic. The main types of magic are earth, wind, fire, plants, and water, but there are rare people who can control special magic like void, lightning , and soul. In order to be an alchemist one needs to be capable in both plant magic and water magic, and to make magical weapons proficiency in both earth and fire magic.

The levels of magic cultivation are:

Condensation - first stage where it's possible to build the energy to use magic at all.

Foundation - Can use magic enough to be useful. A magic adult. Most people end up here. Around 85%. Life span without injury or genetic problem is around 200 years old.

Core formation - the magic gets a mind of it's own somewhat, and can be used without any effort. If this person dies they may leave a curse on the person who killed them or a blessing to a loved one. This is the peak stage for 10% of people. The lifespan is 300.

Nascent soul - the magic is just way more powerful. This magic is willful, as the level mountain peaks, cause tsunamis,  tornados the size of hurricanes, and so on. Your consciousness can't quite die. Now, you'll be slapping faces left and right the entire way up, but this is when peak face slapping gets to conclude. Any country that wronged you: gone, any teacher that gave you a bad grade: fired. People bow down or get blown down. .01% of people reach this stage very late in life. The life span is 500 and you can choose the age you appear.

Immortal- you get to join the special immortal club and live in immortal land, running the world with the other immortals with all of your less cool friends and family as servants in Nirvana. You can only die by other immortals. Like one person in 500 years will reach this stage on the entire planet. Lifespan is ∞

Each level is exponentially stronger than the last. The physical promotion system is the same as the magical system, and nearly everyone has the constitution for it. If someone can grow plants faster and they want to be go to be taken seriously in a bar fight they can train their martial prowess to Foundation stage and mimic the crouching tiger hidden dragon franchise and have the ability to fly on a sword. It's very convenient, so many people do it. Everything else is basically explained enough as we go, and isn't that complicated.