- "We aren't a family, sir! You are the boss! We are the employees!"
- ―Moxxie, to Blitzo
Moxxie is the deuteragonist of Helluva Boss. He is the assassin and weapons expert of Immediate Murder Professionals (I.M.P), a startup assassination business that carries out its services in the living world. He is also Millie's husband.
Moxxie is an imp demon with red skin and white freckles on his cheeks. His white pointy hair leads up to his curvy black and white striped horns. He also has yellow sclera with black slit pupils. Moxxie has a long red thin tail with a quadrilateral barb at the end, as well as lanky digitigrade legs ending in what appears to be cloven red hooves, reminiscent of artiodactylids.
Moxxie's usual outfit consists of a navy-black coat with red buttons and white cuffs, black pants a white shirt that has a black turtleneck, a large red bow-tie, and fingerless gloves. During the episode Loo Loo Land, he wears a plain black suit and tie with no markings and sunglasses while guarding Stolas, just like Blitzo and Millie, but still wears his normal red bow-tie with it.
Moxxie is an Imp who is easily annoyed and rather clumsy, as he trips over their ritualistic book on the way through the portal to the living world. He is the I.M.P's weapon specialist; and as such, has a vast knowledge of weapons. He is often the most vocal of the employees regarding the company as a whole despite its dysfunctional environment and is bullied consequently.
Despite being a murder-for-hire imp, it seems Moxxie has a problem with unnecessarily killing beyond their targets and appears distraught when he believes he almost killed an "innocent" child (Eddie) and can be seen being consoled in a scene in the hospital. He also has a problem with the idea of killing targets who have families, and tries to give people second chances, as seen in Murder Family. He loves his wife's sadistic tendencies and brutality, as he sings of how it makes his heart skip a beat in "Oh Millie".
- Moxxie's name is based on the word "moxie" which means "to have fighting spirit".
- Above Moxxie's nightstand in his bedroom is a framed sheet with a domino mask and a rose pictured on it that says "PAYBILL". This might be an oversight that was supposed to say "PLAYBILL" as masks and roses are common imagery used for theatre.
- It could also be a copyright avoidant reference to the musical Phantom of the Opera, as it seems to be a clip-art styled version of the actual playbill for said show.
- Also, above Moxxie's nightstand is what appears to be a framed vinyl record with a plaque that says "Moxxie".
- It seems possible that Moxxie is or was a musician, as he can sing and play guitar, has a framed music award, has an alarm clock with a musical note on it, and his bedroom and living room wallpaper have musical notes on them.
- With all the musical imagery, it's possible Moxxie's suit is a conductor's suit as it is black, has penguin tails, and has a bow-tie.
- There is a large photo of what could possibly be Moxxie and Millie's wedding photo in the meeting room. In it, Moxxie is wearing a white suit, while Millie is wearing a long strapless black dress and has wild hair that goes down past her hips. It appears Blitzo has drawn over the photo in red marker to draw himself hugging them.
- This same photo seems to be in their living room, although you can only see the bottom half and it does not have Blitzo's graffiti.
- Moxxie makes a cameo in Vivziepop's 2019 short Holidaze as an ornament on a Christmas Tree. Additionally, there is a tree carved with initials "M+M →B←" in a heart that alludes to him and Millie (and by extension Blitzo).
- Moxxie makes a cameo in Hazbin Hotel, appearing as a silhouette in the Boo Section.
- Moxxie is shown to be a good cook. 
- Moxxie does not swear especially often, when in a bad situation he often uses the comparatively tame phrase "Oh crumbs".
- Moxxie is susceptible to motion sickness, as shown by him appearing nauseous when riding a shark in one of the images shown during the I.M.P. commercial jingle, as well as by him vomiting after riding the roller coaster "The Lawsuit" at Loo Loo Land.
- Moxxie is freaked out by theme park mascots, believing them to be perverts under their costumes.
|Main characters||Hazbin Hotel||Charlie • Vaggie • Angel Dust • Alastor • Husk • Niffty|
|Helluva Boss||Blitzo • Millie • Moxxie • Loona • Stolas|
|Overlords||Alastor • Rosie • Valentino • Velvet • Vox|
|Supporting characters||Baxter • Cherri Bomb • Crymini • The Egg Bois • Exorcists • Helsa • Katie Killjoy • Lilith • Lucifer • Mimzy • Razzle and Dazzle • Seviathan • Sir Pentious • Tom Trench • Travis|
|Others||Arackniss • Barbie Wire • Collin • Eddie • Fat Nuggets • Fizzarolli • Robo Fizz • Henroin • Loo Loo • Martha • Mrs. Mayberry • Molly • Octavia • Ralphie • Roo • Stella • Tilla • Villa • Wally Wackford|