Rising Darkness (#19) (Dragon's Fire‪)‬

The dragons return and resume their efforts to keep the Unseen menace from gaining a stronghold on the city. As they reevaluate their plans, a new Unseen in the area begins catching their attention. It doesn't operate according to the way these creatures have for centuries.

One option which presents itself is this Unseen is the large one which Lysander released earlier. If it is, they are in for a considerable amount of trouble. When the dragons and Annabel confront the creature, they find it hasn't returned alone.