Addendum

First of all I would like to apologise that, due to the blog form, part II will appear on top of part one. I do not know how to do it otherwise. On to more practical stuff:

I reread yesterday the relevant part of Eragon and it is Orik, not Ajihad that tells Eragon that the Varden in Farthen Dur number about 4,000 people and from Eragon's comment we are led to believe that this includes non-combattants. So the number of the Varden are not 5,000 at the most that I calculated yesterday, but probably even less.

What yesterday I did not calculate is the maximum possible numbers for the forces opposing Galbatorix. For this we are rather constrained by the need to maintain realistic drama. 5 to 1 is a very dramatic ratio but that can be surmounted if the weakest force is supperior in tactics. 3 to 1 is the standard attack ratio in military manuals in order to insure sucsess in an offensive operation in level fighting conditions. A lesser ratio than that simply does not have enough drama, especially if the Empire was to attack a fortified position. Thus I assume that the Surda/Varden army cannot be larger than one third of the imperial force, or 33,000 soldiers. But lets just round that to 30,000 because too much precision hurts in these cases. As a conclusion I assume that the forces opposing the Imperial army numbered:

Several hundred Kull (this is the only number given in the whole book)

Several hundred of Orrin's cavalry (they cannot be luch smaller or much larger than the force the accompany)

3,000 to 4,000 Varden

15,000 to 25,000 Surdan infantry

A few tens of thousands of Dwarves


These of course are my numbers. If anyone has a better guess I would like to hear them