Tales of the Valiant Players Guide (pg. 129)
You’ve fortified yourself against physically debilitating effects. You gain these benefits:
• Once per turn, when you fail a STR or CON save, you can expend one of your hit dice to reroll the save. You must take the new result.
• When you start your turn blinded, deafened, restrained, or poisoned, you gain 1 Luck.
• You have advantage on checks and saves to avoid being knocked prone, pulled, or pushed.