[quote=@hatakekuro]
<Snipped quote by Zarkun>

I thought that the berserkers needed a drug or something to make them go berserk.

<Snipped quote by Lmpkio>

I will admit, my favorite part of the game is throwing knifes at the target. xD
[/quote]

That's how it was explained away. There was a study sometime ago that found that the German Beserkers had an unnaturally high amount of adrenaline in the bodies, which created warriors that were quick to anger and pretty much never noticed a wound until later. Assuming they survived.