This prediction seems like an easy one to make, Gendry embodies the essence of the Smith. And since Martin likes to use well understood themes, I feel fairly certain Gendry will reforge the sword that was broken – will – I don’t know – get spell support or learn the spell from Thoros, or Melisandre, or the dragon fire will be needed, or both of the above. However the details work out, Gendry will reforge Ice from the two pieces Tywin Lannister broke it into. And it will be the true flaming sword that Jon Snow will wield as Azor Ahai reborn. Will he have to temper it in Melisandre? Daenerys? Arya? I’m sure I don’t know.