Hero Points rule: You are granted 5 + half your level (rounded down) in hero points (so 5 at first level). Hero Points are earned with each level-up–you lose any unspent hero points and your new total is reset to 5+half your level (so Hero Points should be used before they “expire” at level up). Hero Points are used to influence attack rolls, ability checks, or saving throws. Once per roll, you may spend a Hero Point to roll a d6 and add that value to the roll. You have to choose to spend a Hero Point before the results are applied, but you can know whether it is a success or failure before you spend the point.
Alternatively, you can use one Hero Point to turn a failed death saving throw into a success–and this use will be recommended for this campaign. Hero Points should offset some of the difficulty of the campaign.