Ally is a Specification of the Generation Property.

When a Resource is Generated through Ally, the Resource is given by another friendly player in a multiplayer session.

Abstract (Entity) is always found in Archetypes:

Abstract (Entity) is occasionally found in Archetypes:
Ammo, Currency, Consumable, Material

Abstract (Entity) is never found in Archetypes:
Action, Mana, Rage, Skill Point, Physical