The acid rain that falls elsewhere might at most cause unbearable pain. After all, the Flying Dragon King's skin is thick, with a life force of over two hundred points. Shanoba's strong acid breath has only 8D6 (8-48) damage potential.
The upper body was only incidental; Shanoba's target was very clear, it was the wings of the Flying Dragon King. The dragon wings of the Flying Dragon are similar to the leathery wings of Erde, but they cannot withstand this kind of corrosion, and soon they were riddled with holes. Although it's not to the extent of crashing, the flight speed was reduced to a certain degree.
The most fatal was Shanoba's next move, which was to directly bite the root of the Flying Dragon King's right wing and twist it off while refusing to let go.
No need to say more about the rest.
In aerial combat, once one side's flight ability is destroyed, it means the end is near.
