I still remember creating my own army, consisting of cheap Dwarven Runners with low attack and defend, but massive 4 HP, and then boosting their attack/defend ability by adding units that either increased attack/defend for my units or decreased them for the opponents. And since the power of a unit basically seemed to be attack/defend multiplied by HP, Dwarven Runners were the best unit in the game. Also not too shabby when played in a regular army.

But armies of elephants were cooler. As was the mountain where I had my weak goblins collect fire elementals from message quests, and then using those to beat the trolls.