I was trying to find a thread that had a ruling for this but couldn't find one. I was hoping to make a character for PFS that was a Beast Rider, Emissary Cavalier. By RAW, they do not stack because they both alter the Armor Proficiencies of the base class.
Here are the three relevant rules:
Alternate classes wrote:
A character can take more than one archetype and garner additional alternate class features, but none of the alternate class features can replace or alter the same class feature from the base class as another alternate class feature.
Cavalier base proficiencies wrote:
Weapon and Armor Proficiency: Cavaliers are proficient with all simple and martial weapons, with all types of armor (heavy, light, and medium) and with shields (except tower shields).
Beast Rider proficiencies wrote:
Armor Proficiency: A beast rider is proficient with light and medium armor, and with shields (with the exception of tower shields).
Emissary proficiencies wrote:
Armor Proficiency: An emissary does not gain proficiency with heavy armor.
Both changes are not conflicting and they both even imply the same thing (no heavy armor). The only reason this isn't allowed RAW is that they both mention the same change. Would this and possibly others like it be a legal combination for society use?
I didn't have this post initially in the PFS forum because it addresses a RAW rule rather tha a PFS rule. If it would be better there I would hope it was moved rater than closed and possibly thank the admin that moved it.
