By being a vampire, Mina need to sleep a lot, a years and decades in a row. But since she doesn't want to loose her human friends, she sleeps like a human - only every night. Because of this her dreams sometimes are terrifyingly clear and rough. They repeat over and over again, causing her to loose her mind. Some say this dreams is showing her the past, the future, and even the another worlds sometimes. The only way to stop the nightmares to Mina is to draw them.
