What is a good name for a damage type that sounds like it would be effective vs raw health but ineffective vs any armor

brain damage

bacteria damage

piercing damage

Rending

McDonald's

it can be anything if armor = shields

Autistic

Grinding Damage

Raw damage

Slap damage

user have you ever even played a video game, or even learned the very basics of the history of knights?

Sharp damage

Piercing is actually good for armor, depending on how strong your weapon is at piercing. if you can concentrate the force at one point, like on the tip of a dagger, and thrust perpendicular to the armor, and ideally at a structurally weak part, then you can pierce metal armor. its why nowadays we have armor piercing bullets and shells.