|Season 1 Gallery||Miscellaneous Gallery||Season 2 Gallery|
| Character Information|
|Voiced by||Kelly Osbourne|
|Nickname(s)|| Dastardly dumpling; Amorous affliction; Huggable horror; Not-so-gorgeous goblin; Devious diva; Mud muffin(by Grim)|
Witch lady (by Grumpy)
Lumpkin by Duke of Drear
|Age||25 as of "Bummer Vacation" (Younger than the Queen, Starchy and the 7D)|
|Hair||Magenta and Purple|
| Episode Appearances|
|First Appearance||"The Long, Long Winter"|
|Last Appearance||"A Sneeze in Time"|
|Family|| Grim Gloom (husband)|
Duke and Duchess of Drear (parents)
|Significant Other/s||Grim Gloom|
|Enemies|| The 7D|
Hildy is spoiled and often demeaning towards everyone. She says "I want it! I want it! I want it!" whenever she sees something exciting. Knowing Grim's inability to execute evil plans carefully on his own, Hildy often does the planning. Because she's a witch (and one of Jollywood's threats), nobody wants to be friends with her (as shown in "Surprise"). She also bosses Grim around; nevertheless, she loves her husband so much that they usually make kissy noises. Her pure undiluted love for Grim is her only positive quality. Hildy is envious of Snazzy Shazam, her longtime rival who usually bests her. She is also the first-born of her parents the Duke and Duchess of Drear, as revealed in "Bummer Vacation". He also can sing very well; she was taught by her father, the Duke of Drear, who is a musician. In real life, Kelly Osbourne and her father Ozzy Osbourne, who also voiced the duke, are also singers.
Hildy's frustrations with Grim putting a damper on their quest to conquer Jollywood became the focus in "Grim the Genius". After Grim destroyed their home after redirecting a lightning cloud meant for Queen Delightful's castle, he tries to win her back by becoming smart and finally forces Queen Delightful of her castle, making Hildy queen. Initially, Hildy is impressed by Grim's romantic actions. But Grim's intelligence really takes over his personality and he crowned himself king, and he starts to reject Hildy's affections. A heartbroken Hildy misses the old Grim and after losing the Smarty Pants Stone, he reverted to his old simple self. The two embrace, and Hildy says he doesn't need the stone and accepts Grim for who he is, showing that she truly loves him, leading to a mushy, but genuine nuzzling session.
Hildy's biggest weakness is that she freaks out at the sight of slimy things. Even though she loves Grim, she refuses to kiss her husband to make him human because he was turned into a frog once in "For the Love of Cheese". There are a few times the Glooms were forced to retreat due to something icky.
Twenty-five years ago as revealed in "Bummer Vacation", the Duke of Drear was a rock singer who wanted a gold record plaque, so in order to get one he struck a deal with his record producer Rumpelstiltskin in exchange for Hildy, who was an infant at the time. Despite this, however, Hildy and her father are seemingly still in good terms, though the Duke of Drear admitted it was a mistake while his wife, the Duchess, questioned his actions. Rumpelstiltskin, on the other hand, still wanted his end of the deal (it presumably hadn't went as planned although the Duke have his gold record), so he seeks out Hildy and his family, and Hildy doesn't know anything about him.
Also as shown in "Bummer Vacation", there are portraits of Hildy in her various ages at her parents' home. One of her portraits show her levitating a teddy bear with a magic wand when she was a toddler, suggesting that she picked up magic at that age.
Hildy wears a purple sleeveless shirt with several pointed indigo and purple striped collars, an indigo and purple striped skirt, indigo and purple striped tights and purple boots. Her hair is colored with purple and pink. Hildy also wears blue lipstick and purple eye shadow. Both she and Grim have moles on their cheeks; Hildy's on her left. As with Grim, Hildy retains some of her human characteristics when she transform into different forms.
- "Shiny trophy. Me wanty!" ("Sleepytime")
- "Pwease, Grimmy Whimmy?" ("Mirror, Mirror")
- "Eww! Yuck! Gross! Disgusting! Icky! Sticky! Gross! Eww!" ("For the Love of Cheese", at the first sight of Grim as a frog)
- "Bet ya didn't know ostriches can not fly, did ya, lovey?" ("Sneezin' Season", when Grim tries to save her and himself from hitting the ground)
- "Puffiefeathers!" (when she sees the mine locked by The 7D as she, along with Grim, attempt to get the Royal Ruby inside the the 7D's jewel mine while The 7D are away on vacation, "Gnome Alone")
- "There's something wrong with you." (to Delightful in "Gnome Alone", after she does the flips while she yodels)
- "What do you call a crystal ball who cracks bad jokes? Broken!" (to Crystal Ball in "Cat on a Hot Grim Roof" when she is already annoyed of his jokes)
- "The Delightful Diamond Mystery"
- "Starchy Takes a Break"
- "Goldilocks and the 7D"
- "Grampa Grumpy and the Ogre"
- "Bathtub Bashful"
- "New Shoe"
- "Uncle Humidor"
- "Gingersnaps and Grumpy Snaps"
- "The Very Important Thingy"
- "Sir Yipsalot and the Mutt"
- "Finders Keepers" (mentioned only)
- "Big Rock Candy Flim-Flam"
- "In Yer Dreams, Pal"
- "Oh Happy Grumpy"
- "Jollyball Anyone?"
- "The Family Pickles"
- "Dr. Jingleheimer"
- "The Enchanted Forest Ranger"
- "Nicely Done and The 7D"
- "Take Care of Your Elf!"
- "Game of Grumpy"
- "They Growl By Night"
- "Planks, But No Planks"
- "Once in a Purple Moon"
- "A Royal Pain in the Castle"
- The Glooms' transformations
- The Glooms' disguises
- The Glooms' spells
- The Glooms' cauldron
- "I'm Not Very Nice"