On page 37-38, Horn Tusk Armor doesn't make sense.
Horn Tusk Armor
Armor (hide), uncommon
If you fall to 0 hit points and don't instantly while wearing this armor and not incapacitated, you can use your reaction to make a single melee weapon attack.
I would like to point out that WotC has sated several times, that some of the rules are written in a way that the DM is the final word on how it is played. Remember this version is supposed to be story over rules.