Greg responds...

Let's start by saying that the word 'tattoo' is convenient, but not technically correct. These are mystic cryptograms or whatever, and they're only permanent until they are replaced. And, as I think I've said before, a more experienced sorcerer can sublimate the markings so that they're only visible when in use.

Kaldur reached a certain level within a certain specialty. Tula advanced beyond him but in basically the same specialty. Garth has a different specialty, but is more advanced than either of them. Mera, is more advanced than any of her students - at least in Season One.

Certain markings are totemic. Others relate more specifically to the powers.