I fought Firkragg with an average party level of 12 and more or less had an easy time with him... ...
Before confronting him, buff your party up, then enter his lair and summon some creatures. Get your tanks to wail on him while your mages casts Lower Resistance, then cast Greater Malison and get a Cleric to cast Doom. Finally, in the 3rd round... cast something like Feeblemind or Polymorph. Proceed to make Dragon sushi.
Firkragg is just a squirrel at heart. 
I have a list of dragon slaying tips for both low and high level parties. The link is in my signature.
------------------
If not a Sorcerer casting total oblivion, then a Cavalier meting out justice. Otherwise, I think I will just be a Blade and torture my enemies with, "My Heart Will Go On".
Platinium Sorcerer of ALSB,
Aerie
Loving
Sacred
Band! She's MeowRrrr, and more!
-------------------------
Sorcerer Spell List
Dragon Slaying Tips