Hamask

"Odin inspires Berserks to move and attack faster as they lose hitpoints."
In-game description

Hamask is a Norse myth technology that is available to worshipers of Odin and can be researched at the Town Center and Longhouse. Once researched, it makes Berserks move faster and deal more damage when missing hit points.

Effects

Affects	Effect
Berserk	+0.25% movement speed and attack for every 1% missing hit points

Mythology

"Hamask' was the Old Norse term used to describe when a warrior entered the fearsome battle frenzy of the berserks and ulfhednar. Intriguingly, the verb is in reflexive middle voice, suggesting that the warrior 'brought himself into this frenzy or else was possessed by a state of rage."
In-game compendium

Myth Tech