Trolls are similar to minotaurs, but less effective and without self bloodlust.

The spell ingredient brimstone can produce the spells:

meteor shower,

troll and

lightning.

Two out of three spells on this ingredient are the most powerful offensive spells available, and that unfortunately knocks the stong, but cheap trolls out of sight.
The panel is decidely split between lighting and meteor shower: Lightning offers you a pin point damage option, whilst there are plenty of other options for a ranged damage effect like meteor shower. Therefore lighting is too quick and deadly an option to be without.