He extends to you an offer to sit on his War Council, such as it is. The other members thus far are the three other dwarves that were introduced to you, the Grand Masters of one of the demigryph orders to speak for both, the Grand Master of the Winter Wolves to speak on behalf of the combined Nordlander and Middenlander forces, and the Marshal leading the Halflings. The exact position you'll be filling is left unclear - you could be joining merely as a Magister in your own right, or as the most senior Wizard of all those present. It would even be possible to slip into command of the Stirlander forces - you commanded them once, you're sure you could do so again, if you desire.