There's one oddity in this game that puzzled me: the six magic elements used are Light, Fire, Nature, Water, Wind, and... Shadow Frost. That's a rather odd kink in the naming convention, and it's applied consistently within a pretty good localization, so it's not the translators being drunk on the job. But then I started to think about the way magic is presented in the game, and it made more and more sense. The game seems to subscribe to a consistent rule that raw magical power can't hurt people - it can create or effect something to make weapons, but can't strike directly (with the arguable exception of Roland's elemental blades, but that's Master stuff, it doesn't count). This is mostly pretty obvious: Fire, well, duh; Water can be an effective bludgeon in quantities; Nature has vines, thorns and roots at it's disposal; Wind can be shaped to punch someone, or just pick up some debris; and Light can be focused into lasers. But Darkness is by definition the absence of something - light - leaving nothing to use as a weapon. That said, a lack of light also tends to mean a lack of heat, hence, Kill It with Ice, infused with darkness for extra punch. Shadow Frost isn't a hybrid element, the ice just acts as a missile for the dark magic payload.
Which is made even weirder considered that Yuu and Ashley both have different magic skillset than Fatima and it's not even infused with Ice aka Dark Ball, Night Scream and Dark Sphere.