Actually the shadow dragon IS more easy than Firekrag...thalixasyya or something like that is a female dragon and the weight of the attacks are on magic. Firekrag is much more physical than the shadow dragon.
Normally I just chease the dragon...since I´ve got the ward stone...I do not think it is cheasing...but I put up some traps, and then bombard her with killing cloud, death fog and other area spells...it never fails...she drops like a stone