A boss in Super Mario RPG: Legend of the Seven Stars.
Valentina became an aide in the court of King Nimbus several years after the disappearance of Mallow, who is actually King Nimbus's and Queen Nimbus' son ( the heir to the throne of Nimbus Land). She managed to work her way up in the hierarchy of the Nimbus court, and eventually hatched a plot to take control of Nimbus Land by imprisoning King and Queen Nimbus and then passing off her assistant, a large black bird named Dodo, as the prince of Nimbus Land. She would probably have succeeded without the intervention of Mario, Mallow, Geno, Bowser, and Toadstool, who managed to defeat her, spoiling her plans.
After Mario and his friends beat Valentina, she flyes away and lands on top of Booster's Tower and Booster tried to marry her. He surprisingly suceeded.
Valentina has 2000 HP, attack of 120, and defense of 80. She can be hard to beat so you should be at level 18 for all of Mario's friends and Mario before fighting her. In the beginning of the battle, Dodo will take the middle character away and will fight with him/her. If this character dies, the game's over.