I gave him the power to reroll each time you make a roll but you can only reroll once. This wont use up your fate.

And he can use Balefire at craft level 8.

If i'm not mistaken, the Sage has already the ability of re-rolling one time per turn without using up a fate point.

What exactly does the balefire ability do?

Before combat begins in either battle or psychic combat you may use Balefire. If it works you kill the enemy but can’t take him or it as a trophy.

Is this "Balefire" an existing card in one of th Talisman expansions, or is this a new ability you're making up to go along with the character?

I'm not generally fond of "auto-kill" abilities, especially in a game that can (depending on players) rely on PvP. But at least you aren't gaining any XP/reward for pushing the big red button.

PS: The title of this thread is longer than your OP. I'm just sayin' is all. =P

I created a Jester once that had the ability to add or substract 1 from any die roll. If you go with the character you designed, you could use that as an alternative to the re-roll any die once.

If you want to limit the ability I mentioned, make them spend a Fate to use it.