Alternatively randomness could be a special case of determinism. Imagine a deterministic universe that branches into two different universes each time someone in the universe flips a coin. In one branch the coin lands head and the other it lands tails. To the people living inside the universe it would appear like a fundamentally random process, but in fact the universe is entirely deterministic.

In any case this doesn't have anything to do with free will. If you let a random number generator make your decisions for you, that's not free will.