Players in Covens can choose from three paths and become a Master Witch by learning all three.
Casting spells from any one school will align you to their path. The more energy a spell costs, the higher the alignment in it's path, which is why bless and hex won't align you. If your align is changing, you can see on the alignment bar after casting a spell. As your Allegiance to a school grows, your power for those spells will grow too. Mastery of any path will unlock a new very powerful spell.