Orc
Orcs (also called goblins) were a cruel and warlike race that formed the bulk of the armies of Morgoth and later Sauron throughout the history of Middle-earth. Bred for malice and destruction, they were the most numerous of the servants of the Dark Lords and the constant foes of the free peoples.
Origins
The origin of the Orcs was a matter of grief and uncertainty even among the Wise. The most common belief held that Morgoth had bred them in the Elder Days from Elves whom he had captured, tormented, and corrupted, twisting the Firstborn into a debased and hateful mockery. Whatever their making, the Orcs could not create, only ruin and counterfeit, for that was the nature of Morgoth's works.
Nature
Orcs were generally short, broad, and hideous, with sallow or dark skin, fanged mouths, and crooked limbs. They shunned the sun, which weakened and dazzled them, and were strongest by night. They were cruel, cowardly when not in great numbers, quarrelsome, and given to torment and slaughter, yet they could be skilled in mining, tunnelling, and the making of crude but deadly weapons. They hated all things of beauty and all the free peoples, and even hated one another.
In the wars of Middle-earth
Orcs filled the hosts of Angband in the First Age and the armies of Sauron in the Second and Third Ages. They infested the Misty Mountains, the dark places of Moria, and the land of Mordor. The wizard Saruman bred a stronger kind, the Uruk-hai, able to endure daylight, which fought in the War of the Ring. With the fall of Sauron, the Orcs, leaderless and scattered, were broken and hunted down, though they were never entirely destroyed.