Night Raid Decimation

During the Third Great War, Natalay I Shiroko used the first powerful flying Ilyannoi, the Nuzìni. She created these creatures previously during the rebellion instigated by her older brother and husband, Timof III Shiroko. There, they were used to great effect. 
The Third Great War started three years before Natalay I decided to retire. While Eoion lost a small amount of territory as the result of the war, the nuzìni became known across the continent as terrifying threats. To this day, the military of Yzel still tells stories about their capabilities despite the fact that the last one died approximately four hundred years ago.

Summary

The stories are not so much a single narrative, as several rumors that have surrounded Natalay I and her creatures. Most famously, the myth concerns how they were trained and what they were capable of during battle. There are pieces of trust to the stories, which the Shiroko Dynasty encourages when they catch wind of a new tale. 
First, Yzelian soldiers whisper that the creatures were trained Eoin soldiers, which was the only reason Natalay would know they were capable of crushing armor. This is only partially true. She did perform experiments on humans, but instead used death row prisoners and slaves. 
Second, there is a famous story concerning a battle during the War. The Yzelian forces were sitting during the night after several days of quiet along the front lines. The sky was bright, with a three quarter waxing moon lighting the area. Lookouts spotted nothing until the sound of a powerful beating was heard. Most thought perhaps someone had brought a drum, moronic near a battlefield, but something for the officers to deal with. 
In the next moment, panic broke out as three of the beasts descended from the sky. They destroyed walls, mounted crossbows, and carried off dozens of Yzelian soldiers at once. Their eyes were red and their beaks as long as a spear. Each wing was lined in spikes which they used to tear apart the soldiers, leaving body parts strewn everywhere. 
The chaos lasted only for a few moments until nearly the entire platoon was decimated, leaving only a few heavily wounded soldiers as survivors.

Historical Basis

The second story is partially true. There was a surprise night raid during the Third Great War and a section of the Yzelian front line was destroyed. Where the tale becomes larger is the extent of the damage. Dozens of soldiers were not carried off at once simply because the beasts were incapable of lifting so much weight. Three or four were at a time. The tearing and body parts were not due to claws, but to air magic used by the creatures to create miniature tornadoes and slices of air. In the panic, the Yzelian soldiers saw the slices as extensions of the nuzìnis' wings, leading to the belief that they had claws.

Date of Setting

Third Great War (571-573)