First of all, I have to say two things: first I apologize in advance for my English I am not a native speaker.
and second, please read all the text before commenting, reject, accept, give your opinion thank you.
This is not a skill in itself, it is difficult for me to explain
“Mastery” for short is a system that determines how used or how good they are at using certain skills.
You don’t use tp for Mastery instead you get “Mastery Points” using the skill in question and using them to improve in a certain way. your skills each skill has its own “mastery points”. I better use examples so you can get what I mean:
Ultra Instinct:mastery allow to enter ultra instinct and sign at will anytime if both your level on skill and the Mastery is enough for each form.
Kaio-Ken:mastery reduce the amount of damage the player take for use kaioken.
Super Form:each mastery reduce the ki cost of the respective transformation (mastery ss2 = reduce ki cost ss2, mastery ss3 = reduce ki cost ss3, ect.)
Those are some examples of how the mastery would work, obviously not all skills will have a mastery.
I’m going to post more examples here in the future for different skills
I just realized that the super form mastery is a very big buff for saiyans and half-saiyans.
So, to maintain the balance and the logic of Dragon Ball, here is my solution:
Transformations:cooler and golden mastery reduces the ki cost of the respective transformation.
Human Potential:Buff form mastery reduces the ki cost.