If you have the skull in backpack (one per character), that fits. No need to hold on screen.
And yes, the game is hugh, thus the battles become slightly boring at the end.
But there's a reason why the game reached 9 sequels.
Also do not forget your other spell-elements (eg. water). There you have single-target spells.
A good tactic for fighting is to stand in place, shoot until things get in range, then whack them with your mighty halberds, swords, or whatever you have.
PS: even though I could not (yet) find my MM/ certificates, here is something equally awesome:
