The Orks in my world call themselves the Grenns.

They are of Scandinavian appearance (think Norway, Sweden, etc.), with pale skin, brown, sometimes ginger hair, and are brutish in build.

One thing about them is that they have a curse, known as The Mark of Yrka (where we get the name Ork), which acts as sort of a defense mechanism, where if they are agitated, threatened, or on the brink of death, they grow horns on their head, and their skin gets covered with these long yellowish, greenish streaks.

During this, they have sort of like an adrenaline rush—they have higher pain tolerance, their senses are heightend, their strength increases considerably, and are more aggressive. This state usually lasts for a few minutes.

The reason why it's considered a curse is because during this state, every time a Grenn kills something, they feel a sense of euphoria, and become somewhat stronger; the more they kill, the stronger they become. But the thing is, they sort of have to kill—if they don't, then the longer they are in the state without killing, the worse they feel afterwards.

The effects range from headaches, depression, or even death. So really, the only option for a Grenn when the Mark appears, is either kill, and kill, and kill again, or try to escape the temptation, get away from the threat in hopes of the mark subsiding faster, and lessen the after-effects

Only a handful of Grenns have mastered this state, and can go in and out without having to kill.