You've got a love for gambling, and some might say its a disadvantage, but what do they know? You love gambling so much in fact, it manages to tap into your body mentally and physically, giving you a gift of sorts.
When you rage, you can choose to either take the rage as is, or give into gambling and roll a 1d20 to see what happens. If you roll below a ten, then not only do you not rage, but you also lose an action for this turn, and worse if its a 1 you also take 1d4 psychic damage on top of that. If you roll above a 10 then you rage as normal, but the real jackpot is rolling a 20. When you roll a 20 (and you want to go through with this jackpot rage), your hitpoints are recovered completely, and for the next 5 turns (including this turn) you are immortal, You can still be damaged but your hitpoints can't fall below 1. This ability ends after the 5 turns, or if combat ends before it runs out, in which the barbarian cannot roll for rage again until their next level up.
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