"When this kills enemy units, leftover damage hits the enemy player."
Units which possess Overwhelm are indicated by a glowing red fist/gauntlet in the icon slot.
What Does Overwhelm Do?
When a unit with Overwhelm attacks, it keeps going until either it uses up all its damage allocation (attack strength) or it dies. In other words, if the unit with Overwhelm is still alive after killing any blockers the remaining damage hits the opponent's character.
Spells can have Overwhelm as well as Units. The same rule applies: if the spell kills an enemy then any unused damage points hit the opponent's character.
Note that if you target your own units with an Overwhelm spell then the Overwhelm effect does not trigger!
ToDo: clarify with examples
Last updated: 20-02-2017
This page written for Eternal version 1.15, Card Set 1