Maurlene

Maurlene is Grandpa's girlfriend and only appeared in the Diary of a Wimpy Kid Online version of Diary of a Wimpy Kid. She was replaced by Darlene in Hard Luck.

It's unknown how old she is, though Greg says that she looks to be about twenty years younger than his grandfather--Frank's dad is presumably in his late-60s to early-70s, and assuming that Maurlene is twenty years younger than him, she's probably in her late-40s to early-50s.

In the online version, Grandpa Heffley explains that he and Maurlene met when she served him some food in the cafeteria at his retirement home, and they apparently started dating not long after that. Also, despite working as a cook in a cafeteria, she refuses to cook at home.

She and Grandpa Heffley were tasked with babysitting Greg and his brothers for one weekend, and she accidentally left a pair of her underwear at the house (specifically, a pair of leopard-print women's underwear). Until the underwear was revealed to be hers, Susan found them in the laundry and, for a little while, thought that Frank was having an affair with another woman.

Trivia

 * She slightly resembles Isabella.