The first troop you ever unlock, and in all honesty the first troop you should STOP using permanently when you have the chance. Despite the game loading screens mentioning that these are strong against archers or grenadiers, ignore that. EVERYTHING at an equal level kills them easily, except perhaps Skeletons, Storm Maidens and maybe low level Infiltrator Titans. Archers, Grenadiers and Ranger Titans shoot them to bits long before they can hit anything, and every other melee troop type will crush them. On attack they are highly non-economical due to their great ease at getting wounded past the recovery point, and on defense they will simply get shot to bits.