Devour is an ability that wil cause an unit to deal infinite damage to one specified ally unit, with specified requirement, before the attack in battle cycle. If a victim is killed the unit gains Attack Plus 2 and Health Plus 2, if no more victims is available it will instead get Attack Plus -2 and Health Plus -1. (which is not damage to itself, but rather Sap 1 and Negative Protect effect as the health lost cannot be healed) The health drop can be fatal.
An immune ally unit can be killed during the devour process, but the unit cannot devour itself. However it is possible that the unit kills another unit with the same name. The killed units are counted as normal death, and as so the artifacts acting on it will be disposed, and animated might work as well.
List of cards with Devour[]
Human[]
Elf[]
Orc[]
Undead[]
Grave Eater