Extremely weak mutation that is no real threat. Still captured or sought for safety of others.
A viable mutation that works well and is practical but weak in the possession of mutation user.
An average mutant power that can adapt to become higher grade over time if there is practice. Can cause bad things to happen but isn't too overwhelmingly dangerous.
Worrisome mutation that can be used for medium to large crimes or unsafe events. Can be taken down with enough reinforcements if mutant is alone.
Can Level parts or an entire City single-handedly or with a few other mutants. Is possible that a mutant group of level 1's or high tier level 2's can become a level 0 group.
Can easily take over and annihilate cities single handedly with sheer power and force alone. Not many mutants are capable of this and this section is usually applied to mutant groups.