Orcs in the TDDC world were originally the stereotypical D&D orcs - stupid, disorganised and maybe a little stronger than humans. Eventually, thanks to the manipulations of Delvash, they united under the mighty warlord Varharran, going to war with the Elves, Humans and Eladrin in The Shatterwar. In the final battle of said war, Vanharan was slain, but so was the Eladrin King Kelvoras.
Enraged, his lover, the goddess Dialiah, cursed the orcs, vowing that "For a thousand years, nothing shall survive your footsteps". This came to pass in the form of a devastating drought which turned the swampy orcish homeland of Urruk into an unlivelable desert. The massively increased selection pressures led to rapid evolution, turning the orcs into super-soldiers. To put that in perspective, three orcs were considered a genuine threat to Corso's Chasm.
Gruel vs. Urruk
As well as Urruk, a sizeable number of orcs live in the nation of Gruel. Urruk orcs live purely off of banditry and hunting, while Gruel orcs extort local goblin farmers "Magnificent Seven"-style for rice.
Orcs are generally capable of living to about 60, although their actual life expectancy is lowered by their bellicosity. At around 40, Orcs go through a menopause-like process which causes them to develop facial hair. A beard on an Orc is therefore a sign of advanced age and therefore likely above-average fighting ability.