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Myrtle was introduced to The Loud Family in "Insta-gran" by Albert where she had dinner with the family and learned about her children. She came over the next day where she did things that annoyed the children, causing them to resent her over what she did. The Loud siblings conspired to break her and Albert up by making it look like she was flirting with Seymour. After understanding that she doesn't have a family of her own, the Loud children regretted their actions, get over with their resentment over her and even apologized to Albert. As they celebrated Myrtle's birthday, she planned to visit them tomorrow until Albert suggested she reschedule it to Sunday since Albert got tickets to the R.V. show, she also very proud of the children accepted her as their "Gran-Gran".
In "Racing Hearts", she and Albert compete together in the Royal Woods Astonishing Quest.
In "Present Tense", she and Albert appear on a picture inside Lynn Sr.'s scrapbook.
She was shown to be smothering the Loud kids, due to her not having a family of her own. She is also shown to like hanging around with her grandkids.
She has the traits of a stereotypical grandmother, such as making her grandkids sweaters.
Myrtle has a red sleeveless shirt, yellow circular earrings, white bracelets, brown slacks, white slip on shoes, and dark brown hair in a "beehive" style and a black mole around her chin. Myrtle has also been seen wearing a blue and white polka dotted bandanna around her hair.