Larian Studios Forums Baldur's Gate III Baldur's Gate III - General Boots and Gloves

Actaully, it doesn't.

You only gain the general benefits of rage while you're not wearing heavy armour, but wearing heavy armour does not prevent you from raging - you still can. Many subclass features can only be accessed while raging, or only take effect while you are, and all of those are still fully accessible if you're raging and wearing heavy armour, unless the individual feature says otherwise (a couple do, to illustrate that this is intentional). It's of dubious value, and isn't a situation you're ever likely to want to find yourself in, but it is legitimate. One place where this can be used, if you're a barbarian so inclined, is as a Bear totem barbarian - as written, you can rage while wearing heavy armour, but do not gain any of your rage's normal effects, however, you still DO gain the benefit granted by your totem subclass option, which for bears at level 3 is resistance to all damage except psychic. Compare this with the Elk totem - which explicitly calls out that you do not gain its benefits if you are raging while wearing heavy armour; those features of rage that do not call out being inhibited by heavy armour are not.