I beat it on Hard as a chaos magic user without too much difficulty. Mostly using the grease mist + fire rain combo for some decent damage. Later when I got a scroll of blizzard I maxed rune magic and started using that as an opener since you can usually hit every enemy if you get the first move.

Geyser would've been nice for dragons but I didn't get a scroll of that until very late in the game.

You can easily max every talent in the magic tree so do whatever you want, really.