The enemies here are mostly level 26 and 27 (and some level 29 enemies in Dragon Knight Saga). An anti-dragon zone protects the center of the fortress, where Xanlosch, Isabelle, and Stone are. The fortress consists of several platforms at different elevations, which makes use of your dragon form necessary. Unfortunately there are plenty of air defenses, such as ballistas, wizard towers, and nests that make flying difficult.