- "We have to create the ideal world that, um, the count wished for in his heart... A world of love, not war. Yeah, let's all pencil that in. An appointment...of hope."
- ― Nastasia, Super Paper Mario post-game
She is shown to be punctual, and ruthless according to her co-workers. She orders around Count Bleck's other minions: O'Chunks, Dimentio, and Mimi, and is ultimately in charge of Castle Bleck. She also is the one who hypnotised Luigi to be Mr. L. Her name may come from Nasty, Anastasia and Natasha (or Natalia). Once you complete the game she is over at Flopside's 1st heart pillar (World Five's heart pillar).
Conversations with Count Bleck reveal he had saved Nastasia once before, then she swore loyalty to the Count in return for his actions. As well as later on, she reveals subtly to have feelings for Count Bleck, which he dismisses; however, both Bleck and Nastasia have a deep bond, as he offers to let her leave without any punishment, to which she decides to stay due to her feelings of the Count and the debt she owes him for saving her life.
- Hypnosis: As seen on characters like Bowser's minions and Princess Peach, she has the ability to brainwash people.