With the substitution levels from Goliath Barbarian, does the Mountain Rage still give the bonus to Constitution? Or do you lose that in exchange for a size increase and bonus strength?
It’s kind of weird because mountain rage still refers to the process as “rag[ing],” but then explicitly says that it “replaces the standard barbarian’s rage ability,” before finally coming back and saying you also get all the benefits of regular rage.
When [a goliath barbarian] rages, [he gains a number of benefits]
Mountain rage replaces the standard barbarian’s rage ability, and when a barbarian would normally gain extra uses of the rage ability per day, he instead gains extra uses of the mountain rage ability. However, the barbarian gains these benefits in addition to the normal benefits and penalties of his rage (+4 Strength, +4 Constitution, +2 on Will saves, and –2 to AC).
(Races of Stone pg. 150-151, emphasis mine)
So in total, mountain rage confers Large size that replaces1 powerful build, as well as +6 Strength, +4 Constitution, +2 on Will saves, –3 to AC (including the –1 from being Large).
- The description doesn’t actually say that the Large size is a replacement for powerful build; RAW you could argue that you get both. But Races of Stone says “he does not gain additional benefits on weapon size and grapple checks, since he already has them from his powerful build ability.” That indicates that powerful build does not stack with mountain rage’s Large size, or else those figures would see additional benefit (becoming comparable to Huge size).