Miranda was an anthropomorphic duck.
Little is known for certain about Miranda. She was the grandmother of Elvira Coot, though whether she was a paternal or maternal grandmother or, perhaps, a step-grandmother of some sort is unknown. As a young lady, she was kidnapped by a Native American tribe and taken to live with them for several months until she was rescued by the man who would eventually become Elvira's grandfather (whether this is Cornelius Coot, Grandpa Gadwall, or someone else is unknown). During her time with the Natives, she buried some gold nuggets and left instructions in her diary on where to find them.
By 1986, she seems to have passed away as a now-elderly Elvira is the owner of her diary.
was an anthropomorphic duck like his wife. Very little is known about him. He is the one who rescued Miranda from the Native American tribe that had kidnapped her and held her captive, thus becoming her hero. The two seem to have married. Even if they never actually did marry, Miranda's granddaughter Elvira Coot would later refer to this man as her grandfather. Elvira has at least two other grandfathers, Cornelius Coot and Grandpa Gadwall. Whether this man is the same figure as one of them is unknown.
Behind the scenes
Miranda and her husband first appeared in Grandma Duck's Grandma in 1986. Whether she is to be seen as the same character as Pluckahontas or Grandma Hortensia, two other grandmothers of Grandma Duck, is unclear. It is likewise unclear as to if Miranda's husband is the same character as Cornelius Coot or Grandpa Gadwall.
In his unofficial musings on his blog Generation Duck, Xander Ares speculated that she is the same as Pluckahontas, about whom nothing is known other than Don Rosa stating she was a Native American with even her name simply being a fanmade moniker. Xander Ares theorized that "Pluckahontas" was not a Native American by blood and was simply adopted by a native tribe and that Miranda was in fact adopted by the tribe that kidnapped her. He also theorized that Miranda's husband and hero was none other than Cornelius Coot.