Avenging Spirit

"Vidar's spirit causes your Hersirs' hammers to grow mightier with each strike, increasing in size and damage as they fight."
In-game description

Avenging Spirit is a Norse myth technology in Age of Mythology: Retold - New Gods Pack: Freyr, available to research at the Great Hall and Temple if the Mythic Age is reached through Vidar. Once researched, it makes Hersirs gain more attack damage based on the total amount of damage they have dealt, with the visual size of their weapon also increasing.

Effects

Hersir: Gains veterancy ranks from damage dealt to units. Has 3 ranks, achieved when having dealt 50, 150, and 300 total damage. Each rank grants +20% attack.

rank	damage
Laborer	-30% hack and pierce vulnerability

Myth Tech