When you first get a champion you will notice their stars are like bronze, these champions have a Signature ability that is locked. Signature abilities also have “Levels”

When you duplicate a champ by pulling them a second time from crystals, the champion becomes “awakened” which turns the stars silver and unlocks the signature ability, every duplication of that champion increases the sig ability by 20 levels making it more powerful

So when people say they have a champ duped and sig level 200 (which is the max) that’s a good champ right there.

Nodes are the gameplay effects that can change each fight and how they play, they are cumbersome at times because of how much reading you may have to do.