Loving the epic so far (not had chance to finish it yet!), but after the Sunder-battle instance, I've been left with a question. Given that this is involved in the new epic, there are spoilers below for those that haven't got that far yet.

The instance tells us that nine dragons attacked Biriz-zahar in the First Age, and that five were slain.

This means us that four survived. In the instance, we saw:
- Etterfang
- Thorog
- Hrimil

This leaves one mystery dragon who was there and survived, but was not seen in the instance. My bet is either on Smaug (as Etterfang's brother), Thostir the Rank or Draigoch. It would be cool to find out - and to encounter Thostir at some point, given that, after the new raid, Thostir is likely to be the only known dragon left alive.