The Zombie Apocalypse
Orcs originally hail from the wastes of Gamoor, a continent far east of Melthilian. After generations of war and living in harsh, unforgiving lands orcs became a tough, agressive race. Once they had depleted the limited resources available in the wastes, the orcs sailed west to the continent of Melthilian. Seeing that the humans, elves, and dwarves were a mostly peaceful folk, the orcs took them as weak and made designs on taking the continent for themselves. The peaceful folk of Melthilian proved stronger than the orcs anticipated and the war proved long and bloody. When the humans came to the Warchief with a treaty offering that allowed the orcs to keep the lands they’d already conquered, he readily accepted.
As a race, orcs are strong, and physically tough. Most have a strong sense of honor that they protect fiercely. They are trained to use axes from a young age. An orc (or possibly half-orc) racial aspect can be invoked or compelled for these effects.