She is a vampire noble who lives in an abandoned castle.
She looks young, but her actual age may be closer to one thousand years.
No one dares to approach her, not to mention asking her age.

Deemed by the Holy Church as the oldest bloodsucker, she neither grows nor ages.
She only comes out of the castle at night and appears in the Mistforest.
No creature dares to come near when she is walking alone.
On the night of the full moon, as her strength reaches its peak and her mood swings, she can no longer suppress her urge to suck blood so she will destroy all creatures in her path by feeding on every drop of their blood.
Since she is aware of this, she tries to avoid going out at night on the full moon.

She attaches great importance to her aristocratic decency, as is shown in her gorgeous clothes and elegant manners, but she's still naive like a child. As long as you don't mess with her, you won't be in great danger.
She won't attack any creature first unless she's provoked first, which distinguishes her from other lower bloodsuckers.
Eccentric as she is, she gets along very well with Ella and Metamorphoses and often goes out to play with them.
Unlike Ella, Nocturna is careful and sensitive to the slight mood changes of Metamorphoses.

After eating an apple brought by Ella, she became obsessed with its sweet and sour taste. She tried to buy fruit in the market of the town but people there just ran off screaming when they saw her.
She felt so irritated that she brought Metamorphoses along and sneaked into the town to feast in the fruit warehouse.
Though she met with the opposition from Metamorphoses, she could care less because nothing was more important than having tasty apples.
However, out of respect for Metamorphoses' feeling, she finally decided to stop sneaking. Instead, she asked Ella who can freely go to the human town to help her buy apples.