Classes of Champions

Every Champion has a Class (E, D, C, B, A, S),  E being the weakest and S the strongest.

Your Champion's Class will affect the Leadership he has (higher one for higher Classes), as well as the power of his Initial Skill. (Champions of higher Classes generally have better Initial Skills)

Some Champions can evolve to a higher Class when reaching their max level and by using the required materials.

You can see if your Champion will be able to evolve on the Champion Details panel.

For example:

Odin is a class A champion

and Arthur awaken is a class B champion