The Seven Deadly Sins in the Hellverse.
According to Vivziepop, she explains that the 7 Deadly Sins represent each circus act.
1.
Lucifer Morningstar rules the Pride Ring and all of Hell as he represents the ringleader due to his status and attire. An app on Blitzo's phone that says "Lucimaster" probably the equivalent to ticketmaster as Lucifer owns a theme park called "Lu Lu World" and his wife, Lilith does concerts as there is a poster of her in the background in the Hazbin Hotel pilot episode.
2. Satan rules the Wrath Ring, though he never made a physical appearance, but he was mentioned several times by the characters as they use his name to swear and in the pilot episode of Helluva Boss a homeless imp is holding a sign that says "Monee Helps Satan Bless" he would be consider the imps' version of God. In episode "Ozzie's" there's an app on Blitzo's phone that says "Satan's Workouts" as he is mentioned by Beelzebub in "Queen Bee" that she saw him shirtless. Satan would represent the circus strongman.
3.
Beelzebub rules the Gluttony Ring and is Vortex's girlfriend. She throws a ton of crazy hound parties when Vortex mentions her in "Spring Broken". Vivziepop says that Beelzebub represents the animal tamer as she goes through hoops, which she does during the "Cotton Candy" song. An app on Blitzo's phone that says "Bee Eats" the app would be about food delivery.
4.
Mammon rules the Greed Ring, he owns a theme park called "Loo Loo Land" which is a rip-off of Lucifer's Lu Lu World. He represents a jester due to his obvious attire, an app on Blitzo's phone that says "Moneymakerz Bank" which is a banking app.
5.
Asmodeus or Ozzie or Ozz rules the Lust Ring. He is the owner of a club called "Ozzie's" and a factory called "Big Ozzie's Factory" which the sex toys and Robo Fizz at Loo Loo Land are created. He was also responsible of creating the Fizzarolli sex toys, much to his displeasure as it was for Fizz's likeness for Mammon.
When I watched a youtube video of this youtuber called Cartoon Universe as he says that Asmodeus represents a stage magician as he appears on the stage with smoke like most magicians do. The app on Blitzo's phone called "Lustinder" a parody of a real-life dating app called "Tinder". Asmodeus is also the keeper of Asmodean Crystals, a type of magical mineral that gives hellborn demons access to the human world.
6. Leviathan rules the Envy Ring. There's no information about him or the Envy Ring, but there were glimpses of deep sea demons in "Ozzie's", and a mother and son deep sea demon from "Western Energy". In "Mammon's Magnificent Mid-Season Special (ft. Fizzarolli)", the twins, Glitz and Glam might also be from the Envy Ring, because of their fish-features. An app on Blitzo's phone that says "EnVee" a parody to "TikTok".
7. Belphegor rules the Sloth Ring. She never made any physical appearance, but she was mention by Beelzebub when she couldn't convince her to use her party drugs when she wanted to throw a bigger party. Sloth Ring is home to the Baphomets, a candle-headed goat demon and where the medical buildings are located such as the St. An's Hospital in "Western Energy" when Blitzo takes Loona there to get her Hellbies shot and the Rehab Center in "Unhappy Campers" where Barbie Wire resides before she was released.
Cartoon Universe theorizes the Belphegor is a Baphomet and represent the bearded lady. In app on Blitzo's phone is called "Sleepy Pillz" which is to help you sleep better. Belphegor's name is alluded on Stolas' Happy Pills in "The Circus".
Two Loch Ness monsters? Does Nessie have a sister?
Ryuji practices his firebending with Korra and Mako, only one problem he had is their daughter, Naoki. She always beats him despite her being younger and smaller than him. As the years go by he was tired of Naoki beating him, he decided that enough is enough, he will try to beat her no matter how long it takes she will the loser on the matt.
I realized that I mistranslated Kuroi's last name. "Mado" means "Window" in Japanese, the Japanese word for "Widow" is "MibΕjin."