How to create a Custom Skill with custom Animations

So I want to create skills kind of like superhero ones where you can fly and have super speed and super strength and I was wondering how would I make it so a custom skill has custom animations each level up and how to create a custom skill that is only available to those with a certain trait. after all of that how do I make it so when those skills are maxed or reach a certain level they can do things like "Super Speed Here" or set like "always move Flying" or if there is a teleporting skill how to make the teleporting randomized when failing to teleport. all in all, I need to know how to create a custom skill with custom uses and animations.

Thanks,
Bzeebee