Krall

The Krall are aliens that appear in Unreal and Return to Na Pali as enemies in the single player game, Unreal Tournament 2004 in the Invasion, and Unreal Tournament 3 as an enemy team. They are a brown, lizard-like species with large spikes that are more primitive and feral than humans. Their home planet is unknown.

In their original Unreal appearance (and later derivative incarnations) the Krall are relatively Human-like. In UT3 the Krall are depicted much more like vicious, yet intelligent, animal predators. During Unreal and Return to Na Pali the Krall are enslaved by the Skaarj who used them as soldiers. (It is unknown whether they replaced or complemented the Izarian fighting force.) Over time the Krall grew contented fighting for the Skaarj. The Krall on Na Pali are armed with concussion staffs which can fire energy bolts and which can be used to hit nearby enemies with. After losing their legs in combat the Krall will crawl towards their enemy while still firing energy bolts. There are also the Krall Elite recognizable by patches of blue body paint. The Elite are stronger fighter that are better at dodging enemy fire. They are equipped with more powerful concussion staffs. During UT2004 both regular Krall and Krall Elite appear as enemies in Invasion matches. Their appearance is identical to that in Unreal.

Unreal Tournament 3
In UT3 a Krall tribe led by Scythe fight alongside the Necris for reasons unknown. More of their background will surely be told during the single player game.