In my case I just treat Ninjitsu as magic, as all magic lore wise is interrelated and basically all of it comes from Aether, then I just pull from the school of Thaumatology which draws aether from ones self to cast their spells, the only difference being that H'ecate doesn't require a rod/staff as a focus for these particular spells but rather uses her hands or weapons for the focus. So she is basically a rogue who can cast a few spells. I know some people treat it like using magical items etc.. Honestly you can really do whatever you want the lore on magic and aether manipulation and use of crystals is so broad anything is really possible, I mean there is literally a limsa quest to get a guy thunder crystals so he can use the crystal to super heat his rivets he is using to build a ship.
