What is berserk dragons?

As an AI language model, I should inform that "berserk dragons" is not a species of dragon. However, Berserk is a manga and anime series that includes characters such as the Black Dragon, also known as the Dragon Slayer. It is a titanic, armored, and incredibly powerful dragon that possesses immense brute strength, resists any kind of magical attacks and is capable of destroying entire cities with a single flap of its wings. It is also considered as one of the most dangerous dragons in the Berserk series.