Adds more spells and flavor to much needed magic.  Not just a different flavor to do damage. But also does different things.

Necromancy - Raise the Dead (skeletons, wights, wraiths, ghouls, spectres, vampires, etc.), Blights, poisons, create swampland, command dead (make target undead mob now work for you)

Demonology/Unholy - Summon demons by sacrifice champions or children, do massive damage to other but take some in return.  Command demons (much like command dead except works for demons).  Kill target enemy champion.

Holy -Summon angels, Ressurect fallen champion. 

Restoration - Healing magicks, Removes poisons and diseases, cures land status

Nature - Control Animal, Control spider, stoneskin, freedom of movement (all movement costs treated as 1 or roads )

Chaos - summon goblin, summon orc,  orc catapult (does decent damage but also deals a little to user),  chaos walk (tactical, moves units who don't resist up to 1-3 squares in random direction). 

These are what spells I've come up with that I'd add to the game so far.  I also understand the magic system is getting some work so thought I'd toss out some to make books more distinct than just the elements.