I'm skipping the 4th book because there is no Wizard on the cover to go to the real gem of the series, in my opinion, The Haunted Castle of Ravencurse!
A great little tale where the titular Wizard and Warrior must go to rob an old haunted castle because the King is going broke. Yeah, it's a classic dungeon crawl plot, but it also involves a haunted castle, so that's always a bonus. Even getting to the castle, as I recall, was a chore. The British cover featured the Warrior facing down a cyclops, which is boring. The American cover however...
Ha ha! Zombies! This book was published in 1985, before the whole Zombie Phenom, which needs to go away something fierce.
And now the question of the day: What the hell is that wizard doing?
Short answer: fighting a magical duel with a zombie king.
He's front, he's not quite center, he's weaving some strange smokey magical power and there's the zombie king doing the same. I suppose he could be a lich, but the text clearly called him a zombie. This deserves a closer look:
See the other zombies behind him? Yeah, he brought an army.
And here is the Wizard in close up. Is that worry I see on his face?
This is not a time for sparkles, I think you'd agree. Our boy is clearly dealing with something that a simple sparkle or a lighting bolt can't handle.
I have also come to the rather obvious conclusion that no matter where the Wizard is, it's pretty windy. His cloak is always in full dramatic billow. Maybe this is one of those things he learned from his master while he was an apprentice. A simple effect, billow cloak, a cantrip really, but every wizard knows that magic is pretty dull without a bit of theatrics to spice it up.
So the answer to our question, What in the hell is that Wizard doing?--Wishing he was a cleric.