“I'm just gonna pencil you in for a ten o' clock brain washing, K?”
Nastasia is a villain in the game, Super Paper Mario, and is the right-hand woman of Count Bleck, the main antagonist of the game. Unusually for such a high-ranking adversary, though, and unlike the rest of Count Bleck's minions, she is never fought directly; instead, most of Bleck's minions were brainwashed by Nastasia's powerful hypnosis abilities. She can even use it to force people into doing things they would never contemplate in their right mind, most notably when she made Peach marry Bowser so as to allow the Chaos Heart to be created. She functions as if she is Bleck's secretary, trying to keep things running according to his schedule and relaying his orders, even going so far as to repeat them verbatim to give them emphasis. Like many of Bleck's minions, she is very close to her master, having pledged her life to him after he saved her some time before the events of Super Paper Mario. Bleck trusted Nastasia enough to let her know the story about his identity as Lord Blumiere and his lost love, Timpani. Her name is Greek for "She who shall rise up again", possibly a reference to her only falling unconscious from a deadly attack, or the story with the bat and the man. It is also a pun on the word "nasty" and possibly "Anastasia" or "Natasha".
If one goes to Flopside and listens to Carson at the coffee bar, he will tell a story called "Of Bats and Men" (the title of which is a parody of Of Mice and Men). The story talks about a man searching for a girl he loved who is missing. While he is searching, he discovers a bat in a trap and sets it free. Later that night, while the man is sleeping, a woman whom he has never seen appears to him. In the story, it is said that the bat transformed into that woman and pledged, out of love, eternal loyalty to the man. No one knows what happened to them. It is heavily implied that the man is Lord Blumiere, the girl is Timpani, and the bat who transformed into the woman was Nastasia.
Nastasia seems to use her power by lifting her glasses, upon which a white glow flashes and the subject she wishes to hypnotize is instantly under her control. Therefore, it could be argued she has tremendous hypnotic power and wears glasses to control this power. It can be noticed that they are only seen open once. The player gets a glimpse of them when Nastasia is crying over Count Bleck and she rubs her eyes under her glasses. They are seen closed after being knocked out by Dimentio, and she quickly dons her glasses before opening her eyes when she wakes up. Notably, the hypnosis she uses may sometimes cause physical changes in the victim, such as hypnotised Koopa Troopas donning dark glasses and spikes around their neck or Luigi changing both his clothing and his personality after turning into Mr. L.
Late in the game, Nastasia asks Count Bleck if he wanted to stop his plans before it was too late while he muses over whether Tippi could possibly be Timpani. He refused and offered to let her leave with his blessings. She, however, decided to stay, as she had sworn her life to him ever since he saved her. Nastasia appears to have feelings for Count Bleck, but does not want to attempt to reveal this to her master, likely because he is already very troubled by his past love experience with Timpani. In the end she cries due to Bleck's disappearance.
Nastasia was initially by the Count's side when he confronted Mario and Tippi in the center of Castle Bleck, but before the final battle with Bleck starts, he requests Nastasia to leave, a request she reluctantly obeys. After Count Bleck is defeated by the four heroes, a worried Nastasia warps back into the room; her worry turns into panic when she spots Dimentio firing a magical projectile at Bleck, a projectile which seemingly mortally wounded the hypnotic bat woman. However, she is later seen alive and well after the game has ended. When she learns of what the Count did to stop The Void, she starts crying uncontrollably. However, everybody still feels that Bleck and Tippi are still alive somewhere. Mimi and O'Chunks suggest that they build that perfect world that the Count had told them they'd make after disposing of the previous worlds. Nastasia, regaining her composure, agrees. After that, the player may find her on the third floor of Flopside, where she comments on her feelings for the Count, and decides that if she could not learn to love again, she probably never could have measured up to Timpani anyway.
Nastasia makes an appearance in the Super Paper Mario story arc of the Super Mario-Kun, volumes 37 and 38, mirroring her role in the game it is based off of. At one point, she breaks the fourth wall by holding and reading the Super Mario-Kun volume itself.
Names in other languages