[Lolzytripd]

My suggestion is simple, allow stolen spells when used by a shinobi/Spell thief to generate marks similar to how scrolls do as they are now

If that's a bit too expansive perhaps limit it to stolen monster spells only.

[Poruku]

Why would spellthief get that and not mage? I get the kakashi meme but like c'mon, and what about fir for big fireball technique?

[Lolzytripd]

I was thinking spell cards = scrolls

But you really could just mirror the domains down
Nerif= fire marks, issep = mountain marks, talvyd = wind marks, Aquarian = forest marks