"Imps are small, pushy servants of Hell. They are cunning, cruel -- and can be quite persuasive." - From the collected works of His Majesty's Advisor
Small, quick and with a surprisingly powerful attack for its level. Get the Imps before they get your early units. Later in the game, they're more a nuisance than a threat, since most of your advanced and elite troops can kill them with one shot (and tend to have a large Elemental Magic resistance).