Fel orcs are heavily mutated orcs with red skin.
The only instance when in which Fel orcs were active on Azeroth was the Third War. Mannoroth tricked Grom Hellscream and his warriors into drinking corrupted blood. Grom later overcome the rage when he ended Mannoroth alongside Thrall and Jaina Proudmoore. This freed a few fel orcs and regular orcs on Draenor. later, when pit lord Magtheridon took over outland, he created fel orcs by making them feast upon his blood. Illidan Stormrage defeated Magtheridon he was imprisoned and the loyal fel orcs watched over the prison. Illidan later completely took the leadership of the fel orcs creating more. Illidan is experimenting this affect on mag'har to create more. Some have rejoined the Dragonmaw orcs for a short time but later betrayed the Dragonmaw when the Horde come to speak.
- Female fel orcs are yet-to-be-seen, it is confirmed they exist though.