[Endoperez]

About the more demons -items... I think that new spells should be added for lower-level demons, always a level higher than the main ritual, which give one/two more demons per casting and cost more. I'm not sure but they might need more magic requirements too. An example for this:

Get Some Devils
fire-2, blood-3
Blood 4
Summons 2 devils.

Another way would be higher level mages summoning more devils. That is, the rituals we have now would summon 1+ devil(s), and with a mage with blood-4 you would get three devils. We would already ahve the items needed...
Because of the quite abusing pretenders one could make (research level 3 to get the effect of level 9 spell!) maybe these should be national summons. The Devil-variety for Abysia, Frost Fiend -one for Jotunheim, Storm Demons for Vanheim (even if the Jarls still start with blood-1). And maybe Dark vines- summoning for Pangaea? I'm not usre about this, though... The nations would have to START with those spells to get these spells.