Ojīsan and Obāsan

Ojiisan and Obaasan (Japanese for "Grandpa and Grandma") are two elderly Hammer Bros. from the Super Mario Amada adaptation of Momotaro. They are the grandparents of Princess Peach, and the adoptive "grandparents" of Mario. They resemble normal Hammer Bros., except Ojiisan has a small white beard and a mustache while Obaasan wears a pair of glasses. They live near a large mountain in a simple house located on top of an island floating in space. Ojiisan and Obaasan lived a happy and peaceful life with their beautiful granddaughter Princess Peach, that is until the fateful day Bowser and his Koopalings arrived on their island. Bowser was instantly smitten with the beautiful Princess, and thus decided to kidnapped her. Her grandparents pleaded with Bowser to let her stay but to no avail, and she was taken away to Bowser's island of dark spires and skyscrapers. Ojiisan and Obaasan were not powerful enough to save their granddaughter and were forced to adjust to living without her, leaving them lonely and disheartened. However, one night while watching the stars and thinking of Peach, a shooting star fell to earth right in front of the couple. Actually this was no meteorite, but a giant peach that had fallen from the heavens. Before their eyes, the peach split in half and the young boy known as Mario was born. The two Hammer Bros. decided to adopt Mario as their "grandson" and raised him as if he were their own. Many years passed, and their little peach boy Mario turned into a young man. One day, after hearing the story of how his grandparents' granddaughter was kidnapped, Mario decided to save his "cousin" Princess Peach from Bowser's island. Although initially reluctant, Ojiisan and Obaasan eventually agreed to let Mario go on his journey. To help their grandson out, Obaasan packed him some stamina-replenishing Mushrooms, while Ojiisan armed Mario with a gun for the inevitable battle with Bowser. Ultimately, Mario was able to defeat and imprison Bowser and his Koopalings and save Princess Peach. Mario and Peach then returned home to their Ojiisan and Obaasan, with Bowser's treasure horde in tow.

Trivia

 * Despite being a Hammer Brother, Obaasan is female.
 * Other versions of Princess Peach's grandmother have appeared in other media. They include "Grandma Toadstool" from The Super Mario Bros. Super Show and "Grandma" from Super Mario RPG: Legend of the Seven Stars.