Tatics and Melee Commanders

Depending totally on the situation/gem income/weaknesses of your nation and other aspects of gameplay. Making a high powered strike force that is immune to certain elements can be a great asset (especially for the magically focused Ulm and a few other nations)

The Black Lord is a great example of this, as he can be equipped with a Elemental Hauberk, Poison Ring, AMA and a Sword of Sharpness and lead a cadre of 5 Black Knights (On Guard Commander) to hammer into a rearmost position or archer position.

It's not for every game or every opponent, as there is a chance for them dying (and thus losing not only gold but gems as well) but the highly mobile and highly armored knightish units if equipped right can turn battles. They are especially useful with fear causing items.