This creature is the Gurak's main air-to-earth attack force.
They look like giant birds and attack as modern bomber planes, dropping bombs on top of the ground enemy forces to weaken the path for the ground forces to attack.
You can see them attacking during the various Gurak attacks to Lazulis Island, but you only face them head-to-head at Port Lazulis during Chapter 35. The fact that they can only fly means two things: their strategy is to fly in circles around you and drop bombs as they pass through and your weapons won't even reach them, so the only way to hurt them is by firing Burst arrows at them.