User blog comment:JmLyan/Arath, the Power Charger/@comment-10958553-20130801191529/@comment-7481207-20130801205124

Well, all spells that doesn't consume marks deals only damage, and when they do consume a mark, they have similar effect:

Tier 2 hyper mark generates charges.

Tier 2 max mark deals extra damage.

Tier 2 over mark applies CC.

Tier 3 mark empowered are a bit less similar to each other, but all max mark empowered deals increased damage in some way, while hyper marks focuses on hitting more enemies and over marks focus on utility.

And the ultimate is not very complicated by itself, only overdrive allows you to use more comboes.