The Ogres are the monstrous two-headed allies of the Orcs that were brought through the Portal by the WarlockGul'dan after the First War to act as enforcers in an effort to quell needless infighting between the Orc clans. Due to the constant bickering between their two heads, Ogres exhibit less intelligence than even the lowly Peons. Their incredible strength and unnatural toughness, however, make them some of the fiercest warriors in the Horde.[1]
Ogres are advanced ground units. They are fast, strong and fairly durable units that are useful both offensively and defensively.
They are more expensive than Grunts and also require some lumber to produce, but are more cost-effective. Therefore, Ogres will fully replace Grunts once they become available, unless lumber is in desperately short supply.
Like Grunts, their main disadvantage is that they cannot retaliate against enemy ships and Gryphon Riders, and will have trouble dealing with groups of Towers unless supported by long-range units like Catapults or Death Knights.