The Protagonist and former Great Overlord of the Underworld. He was slain in battle against Trillion, but was resurrected through a contract with Faust, a necromancer.
- Asskicking Equals Authority: Inherited the throne after proving himself to be the strongest of the previous Overlord's children, including his older brother Astaroth, who was the original favorite for it though it's revealed in-game that his sister Fegor is even stronger, but she was too feared for her power. He defeated Michael, one of Uriel's allies and Heaven's archangels.
- Back from the Dead: Trillion killed him in their battle. Faust brought Zeabolos back as a zombie.
- Badass in Charge: Earned the title of Great Overlord for being the strongest Overlord. He actually has a few hangups about this, several times wondering privately if his older brother Astaroth, the original favorite for the throne, would have been better suited to the role.
- Chick Magnet: Levia, Mammon, Ashmedia, and Faust all have or develop romantic feelings for him as their Affection values increase throughout the game. There also are implications of his sisters Elma and Fegor having romantic feelings for him in their respective endings. Ruche in her own ending also seems to be implying some kind of attraction(That Zeabolos was too dense to notice). Perpell is pretty much the only girl who doesn't seem to have any romantic implications in her ending.
- Childhood Friends: With Levia, the only Overlord he's not in some sense related to at the start of the game.
- Cool Sword: The True Demon Blade, Blood-Calibur.
- Deal with the Devil: Inverted; he's the demonic Overlord making a contract with a necromancer for his life. Later revealed to be played with in that it's one demon selling his soul to another, as Faust is the daughter of Lucifugus.
- Depower: Lost a good portion of his power after he was killed. What was left of it was sealed into the Ring of the Tyrant by Faust to be given to the other Overlords to aid them against Trillion.
- Despair Event Horizon: He reaches it at chapter 7 when all the overlords are dead, in the final chapter after Elma's, Cerberus's and Faust's deaths and in the bad ending. Whether he recovers or not depends on whether or not the Golden Ending is achieved.
- Foreshadowing: Overlapping with Shown Their Work, Zeabolos never speaks of his contract until it has been completed, is incredibly charitable to his people, and ends up giving most of what is earned to Faust. Never revealing the contract, charity to the poor, and sharing earned treasures are all part of the conditions one must meet when making a pact with Lucifugus Rofocale, the demon Faust's father is based on. Failure to uphold these rules results in the loss of one's soul. Every good ending results in Zeabolos keeping his soul.
- Golden Super Mode: Using the Ring of the Tyrant ends up turning his hair golden and covering his body in a massive golden Crest. His stats in this form start well above what any other Overlord will reasonably reach after training and has a maxed out Protection, granting complete immunity to Trillion's first four attacks.
- He's Back: In the final chapter, he uses the Ring of the Tyrant to reclaim his lost power, along with the power of all the other Overlords.
- Horned Humanoid: Possesses two large, red, horns. The left one is broken off.
- I Gave My Word: In the True Ending. After finally defeating Trillion, he abdicates from his position as Great Overlord and offers his soul to Faust. The Overlords are dismayed, but Zeabolos insists on seeing his part of the contract through.
- It's All My Fault: Blames himself throughout the game for the deaths of his soldiers, his brother Astaroth, and the other Overlords at the hands of Trillion, as well as the destruction of the Underworld.
- Mix-and-Match Man: He looks like one, with various stitched, discoloured body parts. This is due to his body getting horribly mangled by Trillion in the prologue and Faust's efforts to repair it.
- Multicolored Hair: Purple hair with white bangs.
- Improbable Hairstyle: His hair is bound together near the tip, forming an arrow-like shape. How it stays like that is unknown.
- Laughing Mad: If Trillion reaches the Underworld Core.
- My Sister Is Off-Limits!: Ironically, given his former association with the sin of Wrath, the only time in the game he gets truly angry is when he threatens Uriel with bodily harm every time he makes a move on Elma.
- Rapunzel Hair: His hair is incredibly long and forms a pointy arrow shape at the end, like a tail.
- Roaring Rampage of Revenge: Came back to life so he could take revenge on Trillion.
- Took a Level in Badass: In the true ending, after donning the Ring of the Tyrant, he is restored from his zombie state and received the power of all the previous users.
- Too Many Belts: His right arm is covered in belts, as is his left forearm. He also has two larger belts on his hips.
- Walking Shirtless Scene: Doesn't wear a shirt, although he does wear bandages around his lower abdomen.
- Worthy Opponent: Considers Michael to have been a graceful and powerful opponent. Zeabolos honors Michael's death even as he takes pride in his victory.
- "X" Marks the Hero: Has a massive, purple X-shaped scar on his chest.
The necromancer responsible for Zeabolos' resurrection. Her identity is a mystery, but she's not telling.
- Aloof Dark-Haired Girl: Has long, black hair and keeps a distance from others.
- Ambiguously Human: Who and what she is is left a mystery for most of the game. It turns out she's the daughter of another universe's Great Overlord.
- Badass Bookworm: She spends most of the game teaching the Overlords more about magic or working on new technologies to help fight Trillion. Once she becomes the new Overlord of Vanity she quickly takes to combat as well as any of the warriors that came before her.
- Creepy Cool Crosses: Has three crosses of different sizes as Hair Decorations.
- Her hair clips resemble the Katakana for "diagonal", ナナメ (naname). This might be a reference to her designer, Kei Nanameda.
- Foreshadowing: With the Neptunia DLC Faust reacts specifically to the CPUs mentioning they come from another dimension, while everyone else is more focused on the distinction between God and Goddess and Neptune being Neptune. Outside of that she does occasionally slip and refer to the Underworld as this Underworld. Aside from the reveal of her being from an alternate dimension's Underworld, her ending has her making plans to use God as a tool to gain and maintain contact with other dimensions to be prepared for any possible Trillion-like threats in the future.
- Necromancer: Capable of raising the dead with her Soul Grimoire.
- Power Tattoo: Eventually gains the Crest of Vanity on her back.
- Rapunzel Hair: Her hair goes down to her ankles.
- Sexy Backless Outfit: It's hard to see, but her character model sheet shows that her dress is backless, under her coat.
- The Stoic: Rarely expresses any extreme emotion and usually speaks in a calm, level voice.
- Supernatural Gold Eyes: She's a necromancer and she has bright, golden eyes.
- Zettai Ryouiki: Type B with her boots.
The Overlord holding the Crest of Pride, Perpell's older sister and Zeabolos' niece. She is proud and domineering due to receiving advanced education from a young age.
- Bratty Half-Pint: She's extremely rude and frequently calls Zeabolos a wimp for losing to Trillion.
- Cruel to Be Kind: Her grumpy attitude conceals Anger Born of Worry. For instance, she keeps mocking her uncle for perishing in battle with Trillion because she's concerned about his safety, and she's harsh with her sister to try to make her take the situation seriously.
- Cute Little Fangs: She has one, like her sister.
- Good Wings, Evil Wings: Has both at the same time. Both wings resemble angel wings, but are two opposite colours (black and white)
- Heroic BSoD: Has one when she realizes the Agent is her Brainwashed and Crazy father. If you kill him as her, she has a complete breakdown and starts crying right there on the battlefield.
- Horned Humanoid: Possesses four horns, two on each side of her head.
- Idiot Hair: Has a prominent one, although she's no idiot.
- Insufferable Genius: She received special education from a young age and is selfish and prideful.
- Jerk with a Heart of Gold: She's snarky and rude, but she never aims her snark at her sister and grows genuinely upset as her friends die.
- Meaningful Name: Her name comes from Lucifer (Ruche, as in Luce), who is the patron demon of Pride.
- Only Sane Man: Part of the reason she's so prickly is that she feels she's the only one with any common sense. It's hard not to agree with her.
- Parasol of Pain: Beholder, which has teeth and a giant eye. Her sister admires it, such that one of Perpell's best gifts is a similar parasol.
- Power Tattoo: The Crest of Pride is on her chest.
- Pride: She holds the Crest of Pride. Ruche is a prideful girl that thinks that she's more suited to be Great Overlord than her uncle.
- Rapunzel Hair: Her hair reaches her ankles.
- She Is All Grown Up: Her ending has a scene that takes place a few years after the death of Trillion, revealing her to have grown an extra set of wings and is much taller.
- Tsundere: A non-romantic example, but Ruche's sharp tongue conceals her caring heart, and she's worried whenever she's harshly scolding people.
The Overlord with the Crest of Envy and Zeabolos' childhood friend. She's respectful of Zeabolos in public, calling him 'Great Overlord', but gets touchy-feely in private.
- Anime Hair: Asides from being blue, her hair has two horn-like protrusions that stick out about a foot beyond her head.
- Blade on a Stick: Jenvious, her spear-anchor.
- Can't Hold His Liquor: Gets more-or-less instantly drunk off a single cup of alcohol during the big dinner before the first battle with Trillion.
- Childhood Friend Romance: What she desperately wants with Zeabolos, and gets in her ending.
- Clingy Jealous Girl: Radiates extreme hostility whenever it looks like Zeabolos is having an enjoyable conversation with someone else.
- Dying Declaration of Love: Should she fall fighting Trillion, she'll give one to Zeabolos.
- Envy: Possesses the Crest of Envy. She's also prone to jealousy and dislikes it when anyone gets too close to Zeabolos.
- Heroic Sacrifice: In her ending, when she learns that Zeabolos intends to honor his deal with Faust for his soul, she intervenes and offers half of her own to ensure that he survives. Luckily, Faust is willing to take that offer and both of them survive to get married.
- Meaningful Name: Her name comes from Leviathan, the patron demon of Envy.
- Power Tattoo: The Crest of Envy is on her butt.
- She's Got Legs: Her outfit reveals the entirety of both legs, which are accented by her thigh-high boots.
- Too Many Belts: Has multiple belts on her arms.
- Trademark Favourite Food: Demon Macarons. They're one of her best gifts.
- Undying Loyalty: To Zeabolos.
- You Gotta Have Blue Hair
- Zettai Ryouiki: Type B.
The Overlord holding the Crest of Sloth and Zeabolos' older sister. She's quiet and very lazy, but cares deeply for her brother.
- Affectionate Nickname: Refers to her brother as 'Zebo-chin,' and has similar names for the other Overlords.
- Awaken The Sleeping Giant: The other Overlords treat her waking up as this. She has magic surpassing that of Zeabolos, making a force to be reckoned with when provoked.
- Brilliant, but Lazy: She's the one who teaches the overpowered Multi Strike skill, and she's incredibly powerful. She's also a perfect fit for being the Overlord of Sloth.
- BrotherSister Incest: In her ending she expresses disappointment when Zeabolos kisses her hand, and claims he should kiss somewhere else(Implying lips) to show his dedication, while also asking him to call her by the name rather than "sister". Zeabolos seems to go along with it before the scene abruptly ends.
- Buffy Speak: Her method of trying to explain to Ruche how to adjust her magic in order to best Ragon during training is that it needs to be "kaboom!" instead of "phoosh!"
- The Dreaded: Surprisingly treated like this by the rest of the cast. Less surprising when you learn she racked up the single highest bodycount during the last war with heaven and is more powerful than her Great Overlord brother. She wasn't lazy back then, she was deliberately assigned the crest of Sloth so she wouldn't cause trouble during peacetime.
- Meaningful Name: Her name comes from Belphegor, the patron demon of Sloth.
- Nice Hat: Has a green hat with two round, swirly ears.
- Power Tattoo: The Crest of Sloth is on the bottom of her right foot.
- The Quiet One: Doesn't talk much.
- Sleepy Head: Spends most of her time asleep.
- Sloth: Holds the Crest of Sloth and is incredibly lazy.
- Trademark Favourite Food: Pickled Shark, one of her best gifts.
- You Gotta Have Blue Hair: Bluish-green.
The holder of the Crest of Greed, she desires to fight Trillion for the chance of becoming Great Overlord and attaining all the wealth in the Underworld. She used to oversee the Gate of Hell, but abandoned her post to look for treasure.
- Adventurer Archaeologist: Loves hunting down and plundering old ruins. In fact, the reason she survived Trillion's initial assault on the Gate of Hell is that she'd abandoned her post to loot one. She starts with natural ranks in Item Drop and Gold Drop skills, her high speed makes it easier for her to dodge traps, and she imparts Reflexes and ranks in those skills when beaten in duels.
- Bare Your Midriff: Her outfit bares her entire torso.
- Bling of War: Has quite a bit of fancy gold pieces on her outfit. The piece on her chest actually belongs to Ruche, which she got after the two of them had a little brawl the first time they met.
- Cannot Spit It Out: Once her Affection values start rising, she gets very flustered when she sees Ashmedia flirting with Zeabolos and manages to both disparage wives as "things that suck the money out of a person"... and demand to be the first to know when Zeabolos finally chooses his wife, stating ones like Ashmedia are no good.
- Dual Wielding: Wields two daggers.
- Dying Declaration of Love: If she falls to Trillion, she'll give one wishing she managed to keep her promise to come back to Zeabolos.
- Fiery Redhead: Boisterous and brazen, with a head full of red hair.
- Fingerless Gloves: They show off the crest of Greed on her hands.
- Former Teen Rebel: Mammon didn't have the greatest relationship with her adoptive parents, always suspicious that they didn't like her running off to the slums. She rebuilds bridges with them over the course of her training period, and regrets not being able to enjoy their newfound good relationship more if she dies.
- Fragile Speedster: She starts with a high speed, but lower other stats. Her training is all about learning to use her speed with great precision.
- Greed: Holds the Crest of Greed. She's also selfish and desires all the treasure in the Underworld. Subverted in that her greed might be for treasure, but the money she hocks it into? She's downright charitable with that. She flat-out states this when in her ending when she declares herself Zeabolos' wife as her first act as Great Overlord.
- Meaningful Name: Mammon is the patron demon of Greed.
- Horned Humanoid: Two short, black horns with white markings on them.
- Kissing Cousins: She's Zeabolos cousin, albeit by adoption, and she starts to fall for him as her Affection values rise.
- Power Tattoo: The Crest of Greed is on her right palm.
- Rags to Riches: Went from an orphan living in the slums, to one of the Overlords of the Underworld.
- Scarf Of Asskicking: It's really long and also serves as her top, since she lacks a shirt. The end also functions as a third arm since it ends in a claw.
- Innocent Fanservice Girl: She doesn't worry about being spotted nearly stark naked in a hot-spring event, even offering to let Zeabolos wash her back.
- Stripperific: Her outfit doesn't leave much to the imagination, what with only having a scarf for a top.
- Supernatural Gold Eyes
- Tears of Joy: In her ending when Zeabolos confesses and returns her love.
- Uncle Pennybags: She takes all the treasure she earns while adventuring and freely gives it away in the slums where she was born. Zeabolos comments that she could build an Underworld where there is no difference between rich and poor if she wins out.
- Underboobs: Her scarf leaves her lower boobs visible.
- Who Wears Short Shorts?: The right leg has a fuzzy cuff, while the left leg is covered by a belt.
- Zettai Ryouiki: Grade D.
The Overlord in possession of the Crest of Gluttony and Zeabolos' niece. Ruche is her older sister, but they couldn't be further apart in personality.
- Because You Were Nice to Me: Has been attached to Zeabolos since she was young because he always gave her candy.
- Big Eater: A lot of her events involve her eating something, and much of her training is motivated by her hunger for candy.
- Fashionable Asymmetry: Her right leg has a black-and-orange thigh-high stocking with an orange shoe. The left leg has a black belt on her calf and a black shoe.
- Girlish Pigtails: Possesses two long pigtails and has a childish personality.
- Hair Decorations: A big, round eyeball hairclip and a black ribbon. The ribbon moves in a manner similar to rabbit ears in cutscenes.
- Gluttony: Holds the Crest of Gluttony. She's extremely fond of sweets and eats like a horse.
- Idiot Hair: Perpell has two large idiot hairs sprouting from the top of her head.
- Improbable Weapon User: Uses a large lollipop as an axe. It's bigger than she is.
- Odd Name Out: All the other Overlords are named after their respective sins' patron demons. However, Perpell's name doesn't directly reflect Beelzebub, the patron demon of Gluttony. Be and Pe are visually similar, the difference being a dakuten and handakuten, making her name just slightly off of "Belbel" which would come from Beelzebub.
- Power Tattoo: The Crest of Gluttony is on her tongue.
- Sibling Yin-Yang: The sweet, open, positive, easygoing air-head to Ruche's prickly, Tsundere upper-class strictness.
- Sweet Tooth: She loves sweets and wants to turn the Underworld into a kingdom of sweets.
- Tender Tears: When she sees Zeabolos for the first time as a zombie and blames herself for leaving the Gate of Hell unguarded, and if she falls in the battle against Trillion.
- Third-Person Person: Often refers to herself in the third person, showing her childish nature.
- Too Dumb to Fool: During her training, her instructors find her simple-mindedness to be an asset to her, allowing her to react instantly with a mind clear of distraction.
The Overlord holding the Crest of Lust. She's a seductress with a kink for the cries of her dying enemies. The prospect of killing Trillion has her shivering in anticipation.
- Affectionate Nickname: Calls Zeabolos 'Little Zeabolos'.
- Asskicking Equals Authority: She notes that after her, Overlords were chosen not by their bloodline, but by their raw power. However, she's held onto her post anyway.
- Collared by Fashion
- Combat Sadomasochist: Enjoys dishing out and receiving pain in battle. Her training involves taming it, so that she doesn't get so wrapped up in the pleasure she derives from causing pain that she fails to keep focused.
- Gainaxing: The touch screen causes her boobs to bounce around, something not shared with most of the other Overlords.
- Heroic Sacrifice: In her ending, she offers her own soul up in exchange for Zeabolos' when Faust comes to collect. Faust accepts this and years later returns with Ashmedia as an Empty Shell, warning Zeabolos that while there's a chance she'll recover it's not likely. Luckily, she does and she and Zeabolos reaffirm their love for each other.
- Horned Humanoid: Has two mismatched horns. The left has one bend and points up, while the other one bends in a zig-zag pattern.
- Horny Devils: She doesn't feed through sex, but she fits the bill nonetheless. Horns? Check. Seductress? Check. Constantly horny? Check. Attractive? Check. Hilariously, when she starts falling for Zeabolos for real she shows a much more vulnerable side in their interactions, as well as the little reveal she's never actually had sex with anyone.
- Impossibly-Low Neckline: God knows how her top stays on.
- Kissing Cousins: She's Zeabolos cousin by blood, and despite her usual attitude towards Zeabolos she starts to legitimately fall for him as her Affection values rise.
- Lady Drunk: Played with. She likes her booze, but has an iron liver.
- Loves the Sound of Screaming: The screams of her dying enemies gets her hot and bothered.
- Lust: Holder of the Crest of Lust. She's a kinky seductress that likes to tease Zeabolos, and draws great sadistic joy from combat that sates her bloodlust. Although, it turns out she's never actually had sex with anyone, and in fact when briefly pushed into a position that results in her and Zeabolos sharing a bed, she drops the teasing nature and becomes completely submissive.
- Meaningful Name: Her name is similar to Asmodeus, the patron demon of Lust.
- The Mentor: In a weird way. According to Zeabolos, she was the one who originally inspired him to become the next Great Overlord after his father and challenge his brother for the role.
- Mismatched Eyes: Her right eye is black with a bright pink iris.
- Peek-a-Bangs: The right side of her face is entirely covered by her bangs.
- Power Floats: When fighting, she doesn't let her feet touch the ground, or handle her weapons herself. Instead, she lets the power of her mind handle everything.
- Power Tattoo: The Crest of Lust is around her right eye.
- Shameless Fanservice Girl: As expected from the holder of the Lust Crest. At least part of it seems to be a show she puts on, however, as while she is a master of teasing she's never actually had sex before.
- Stripperiffic: Her bares a lot of skin. Her outfit includes:
- The Tease: She likes hitting on Zeabolos with innuendos, and getting the more-innocent other Overlords to do things like sleep in his bed. Of course, she turns out to actually be very chaste on the inside.
- Unexpected Virgin: Much to the surprise of Zeabolos, she's actually very chaste.
- You Gotta Have Blue Hair: Bright pink.
Zeabolos' little sister. She's frail and often stays indoors because of this.
- All-Loving Hero: She cares for Uriel after he falls from Heaven, despite his people and hers being ancient racial enemies, and even makes peace with Heaven in her ending.
- Big Brother Worship: Adores Zeabolos, who she calls 'Dear Brother', and looks up to Fegor, her older sister.
- Disability Superpower: Her synesthesia is brought up in one training event. She avoids Ergo's attacks by paying attention to the color the sounds make. Specifically while observing the other girls' training sessions she's learned that red sounds need to be avoided.
- Father, I Want to Marry My Brother: In her ending, she mentions always having had a big crush on Zeabolos as a young girl. Considering how, in-context, the conversation's about Uriel's crush on her and Zeabolos's jealousy, it might be implying it goes even further.
- The Heart: Elma is a sweet girl and provides her brother and sister with emotional support.
- Horned Humanoid: Has two red horns, like Zeabolos.
- Ill Girl: She's frail and gets sick easily. She carries around an IV drip full of bubbling purple liquid everywhere.
- Kill the Cutie: if she loses against Trillion.
- Oblivious to Love: She doesn't seem to understand that Uriel clearly has a massive crush on her, or why her brother's incensed and jealous whenever he gives her gifts.
- Phlebotinum Battery: The Ring of the Overlord gives her the power to move and run around for the first time in her life.
- Power Tattoo: Eventually gains the Crest of Gloom on her left shoulder.
- Took a Level in Badass: If the player retrieves Astaroth's soul, it gives her his power.
Once the feared watchdog guarding the Great Overlord's castle, Cerberus is now an adorable ball of fluff. He is now Elma's pet.
- Brought Down to Badass: Even in puffball form, he can take on Trillion and do as much damage as any of the humanoids. Makes sense, since he's the only character to survive going anywhere near Trillion without the Ring of the Tyrant and weeks of training.
- Depower: He used to be much bigger and more fearsome, but lost much of his power due to miasma.
- Eloquent in My Native Tongue: To the audience (and Uriel and Ergo), he just makes barking noises. To the other characters, he's speaking very clearly.
- Hellhound: What he used to be before the miasma. He was feared by many for his claws and fangs. He even had three heads!
- The Power of Hate: If Elma dies, his desire for revenge allows him to awaken as the Overlord of Wrath.
- Power Tattoo: Eventually gains the Crest of Wrath on his belly.
- Ridiculously Cute Critter: He's an adorably round ball of fluff with tiny bat wings and a tail. He's so small that his collar has to go around his midsection (not to mention that he doesn't really have a neck anymore).
- Trademark Favourite Food: Demon T-Bone Steak.
- Vocal Dissonance: Even in the sole scene he has in his fearsome hellhound form, he still has the cute puppy voice.
A monstrous being made of a trillion curses. It possesses an instinct to devour the Cores of the three realms. In the first Great Overlord's reign, it nearly obliterated the Underworld.
- Barrier Warrior: Trillion's final form adds this to its already impressive offenses, with three varieties of barriers.
- Any skill or spell used against it will never work again during the same fight.
- "On The Dish" forms a wide area barrier around both the Overlord and Trillion, with little to no room within it outside of its attack range.
- "I Don't Like You!" forms a small barrier around Trillion that forces the Overlords back and will not let them enter. The only way to attack during this time is to have a range boosting seal on your weapon or have enough skills to wait it out.
- Big Bad: Defeating it is the goal of the game.
- Bishōnen Line: From giant monster to a vicious dragon, and finally to a young-looking woman. Justified in that she was once a Fallen One like the other Overlords.
- Damage-Sponge Boss: May very well have reached the logical conclusion of this trope by possessing one trillion HP. Even early on the Overlords' attack can shave off tens of millions of points per hit, it still only amounts to Scratch Damage in comparison.
- Eldritch Abomination: It's a giant that wanders universes to consume their very life force, and is nearly impossible to approach, let alone harm. As she loses HP, her form gradually collapses until she returns to being a Humanoid Abomination.
- Flunky Boss: It regularly spawns minions, and later miniature duplicates to protect itself. Notably, its second form's hands start the fight on the board, and can take a lot of punishment.
- Foreshadowing: Notice how it has an extra mouth around its stomach area that very similar to Perpell's clothing choice? Turns out, she was an Overlord of Gluttony like her once.
- From Nobody to Nightmare: She wasn't "nobody", but she was once an Overlord of Gluttony — yes, like Perpell — before she consumed her home dimension's Core for revenge against her God and grew addicted to the taste, losing her sanity and free will in the process.
- It Can Think: While it acts very much like a wild beast and Faust even states it doesn't really have a mindset out of killing and destroying anything that's in the way or attacks it, Trillion at multiple points shows a certain degree of intelligence and malice outside of a supposedly mindless monster. This is shown in special detail in the rather brutal methods it takes in killing the fallen Overlords and well as reviving Astaroth as "Agent" to serve as its mouthpiece despite having little reason to.
- Love Makes You Evil: The reason why she consumed her Underworld's Core and began multiversial destruction? Because she was consumed with rage and loss at the death of her Great Overlord, who was love of her life, and wanted revenge for it. Unfortunately, her mind couldn't handle it and by the time of the game she seems to have completely forgotten why she started her destruction in the first place.
- Meaningful Name: It's known as Trillion in the Underworld and is both made of a trillion curses and has a trillion hit points.
- Multiversal Conqueror: It's an invader from another universe it likely destroyed, among several others.
- Poisonous Person: It radiates a miasma so noxious that only Overlords and people under their direct protection can approach it, and then only when it's awake and not intentionally generating the stuff.
- Proactive Boss: Many of Trillion's attacks have incredibly long ranges, forcing you into avoiding several of them long before you're ever in range to begin attacking yourself.
- Rage Against the Heavens: Her original motive was revenge against God for the death of her lover, who was the Great Overlord of her dimension, but devouring the Core of her homeworld destroyed her sanity and all emotions except hunger and rage.
- Red Baron: "God of Destruction". Each of its forms have one as well. Titan Trillion is "One Who Devours All", Dragon Trillion is "Hungry Dark Dragon", and its final form is "Force of Despair".
- Samus Is a Girl: Her final form is distinctly female, and in the true ending is revealed to have been a female Overlord of another universe.
- Was Once a Man: Was once a normal fallen one, at any rate.
- You Will Not Evade Me: While most of its wind abilities are knockbacks, occasionally they will instead act as a vacuum in order to keep you in range of its attacks.
A mysterious agent of Trillion.
- Ambiguous Gender: The official English site refers to Agent as "it". This is mostly to help hide its true identity.
- Character Tics: Running a hand through its hair. In a remnant of its old identity, this is something Astaroth did when he was being dishonest.
- Everyone Calls Him "Agent"
- I Surrender, Suckers: Offers to leave the Underworld in peace if Zeabolos offers up the souls of all the Overlords to feed Trillion. Ruche correctly deduces this is a lie to get them to lay down all the Underworld's defenders and make Trillion's job easier. After all, a girl knows when her father is lying.
- The Mouth Of Sauron: It speaks on behalf of the monster to the heroes.
- Rapunzel Hair: Reaches its feet. Even longer than as Astaroth.
- The Reveal: He's Astaroth, brainwashed by Trillion as her ambassador and general.
- You Gotta Have Blue Hair: Long lavender hair. Just like Astaroth.
Zeabolos' older brother, and Ruche's and Perpell's father. He holds the Crest of Gloom and guards the Great Overlord's castle with Cerberus.
- Absolute Cleavage: His outfit leaves his chest and stomach exposed.
- Amazing Technicolor Population: His skin is blue.
- Eaten Alive: His fate after failing to defeat Trillion. Except not quite, as he comes back as "Agent".
- Hell-Bent for Leather: Wears a full-body leather catsuit.
- Horned Humanoid: Possess two long, straight horns extrending from his forehead at an angle.
- Long-Haired Pretty Boy: He's basically Zeabolos pre-zombied state, but slightly less muscled and lacking his tattoos.
- Nice Guy: He shows nothing but respect and care for Zeabolos and Elma in his short appearances, and by all accounts from the characters in-game he was a great brother, a well-loved leader, and a good, if somewhat distant, father to Ruche and Perpell.
- Skeletons in the Coat Closet: Wears what seems to be dragon bones.
- The Tell: He brushes his hand through his hair when telling lies. Most characters don't pick up on this trait of his, but it's what clues Ruche into Agent's identity almost immediately.
Wife of the first Great Overlord Satan and Zeabolos' grandmother. She once held the Crest of Vanity, but died in the battle where Trillion first appeared. Now she haunts the Great Overlord's castle as a ghost.
- Berserk Button: Paired with Insistent Terminology. Never refer to her in a way that makes her sound old, if her grandchildren and greatgrandchildren aren't referring to her by name it should be that she's "Sister".
- The Corrupter: Tries to convince Uriel to fall, mostly by pointing out that he'd be free to love whoever he liked then.
- Exotic Eye Designs: Her pupils are star-shaped.
- Fog Feet: Her lower half is just a ball of purple fire.
- Heroic Sacrifice: Gives up herself in Elma's ending so that neither she nor Zeabolos would have to lose their souls.
- Idol Singer: She's described as the Underworld's host idol on the official site.
- Horned Humanoid: Two black, curved horns on either side of her head.
- Ma'am Shock: Hates being called "Grandmother," and insists Zeabolos instead call her "sister."
- Mom Looks Like a Sister: Despite being Zeabolos' grandmother, she looks young enough to be his daughter. The fact that she's a ghost may have something to do with it...
- Our Ghosts Are Different
Zeabolos' butler and the Underworld's minister. He's been around since the first Great Overlord ruled and has encyclopedic knowledge of the Underworld's history.
- Anime Hair: The top of his hair sprouts up into two horn-like shapes.
- Amazing Technicolor Population: Has purple skin.
- Gag Nose: Has a very pronounced nose.
- Mr. Exposition: As the walking encyclopedia of Underworld history, Baphomet explains many things to the other characters (and the audience).
- Non-Action Guy: To his frustration. In a later event, he tries to force his way into Faust's laboratory and demand that he be fashioned into an anti-God suit, only for Zeabolos to talk him down by pointing out that he's serving a vital support role.
- Top-Heavy Guy: Compared to his body, his legs and feet look tiny.
- Undying Loyalty: He's been devoted to Zeabolos since his master was a child. However, Baphomet can be a little overprotective.
A high-ranking Fallen One who helps to train the Overlords. He's really strong and is a tough veteran.
- Big Red Devil: He has many classic devil characteristics, including red skin, horns and bat wings.
- Cigar Chomper: Shown chomping on a cigar (emitting purple flame) in his official art.
- Epic Flail: His weapon a giant ball and chain set.
- Foil: To Ragon. In appearance, Ragon is a green dragon humanoid while Ergo is a red top-heavy devil. Ragon is calm and collected, while Ergo is boisterous and loud. Their fighting styles are also different, with Ragon relying on a rapier and precise blows, while Ergo fights with brute strength and a ball-and-chain.
- Red Oni, Blue Oni: Red to Ragon's Blue. He's big, loud and fights using brute strength. Bonus points for also being red-skinned.
- Sdrawkcab Name: Ergo, Ogre
- Too Many Belts: His entire outfit (if you could call it that...) is made of belts.
- Top-Heavy Guy: His torso is much bulkier than his legs.
A high-ranking Fallen One who helps train the Overlords. Compared to Ergo, Ragon is cool and collected. He uses a rapier for delivering sharp jabs.
- Badass Longcoat: Wears a very impressive black, likely military-dress, coat.
- Draconic Humanoid: He looks like a green, bipedal dragon.
- Foil: To Ergo. In appearance, Ragon is a green dragon humanoid while Ergo is a red top-heavy devil. Ragon is calm and collected, while Ergo is boisterous and loud. Their fighting styles are also different, with Ragon relying on a rapier and precise blows, while Ergo fights with brute strength and a ball-and-chain.
- Magic Knight: He oversees both forms of magical training.
- Red Oni, Blue Oni: Blue to Ergo's Red. He's smaller than Ergo, cool and calm, and fights using a rapier and refined techniques.
The monitor who watches over the Valley of Swords, a place where Overlords test their skills. She prevents the beasts corralled in the Valley of Swords from escaping.
- Dominatrix: Has this image, being a stern woman who carries a riding crop and giant handcuffs, dresses mostly in black leather, and is responsible for containing and corralling the beasts used as training fodder.
- Whip It Good: Carries a long, red riding crop.
- You Gotta Have Blue Hair: Icy pale blue.
A blacksmith living in the city near Zeabolos' castle. She can strengthen weapons with magic and enchant weapons via Magic Seals.
- Drop the Hammer: Pictured with a massive hammer in the official art.
- Everyone Calls Her "Blacksmith"
- Ultimate Blacksmith: Uses magic to strengthen and enchant weapons.
- You Gotta Have Purple Hair
A waitress who works in the city's tavern. Always has a smile on her face, but has a sharp tongue.
- Curtains Match The Windows: Blue hair and blue eyes.
- Girlish Pigtails: Supposed to help make her look more cutesy, to contrast more with her sharp tongue.
- Pay Evil unto Evil: Downplayed. She is a very good waitress, but takes ruthless, snarky, and occasionally nauseating vengeance on rude patrons.
A mechanical puppet Faust created, it's used for mock training against Trillion.
- Cloning Blues: One event has him expressing concern that his only purpose is to be a copy of Trillion, and that when the fight is over he'll be thrown into a fire as useless.
- Ditto Fighter: Based on the data inputted into it, it mimics Trillion's appearance and moves. But it's still much weaker than the real Trillion.
- Metal Slime: The best way to get an absurd amount of experience in this game is to overkill Mokujin in its first form. The experience gain gets degraded after awhile since Mokujin will have more HP than before.
- You Cannot Grasp the True Form: He is unable to copy Trillion's final form.
The doctor who cares for those injured from vigorous training.
- Amazing Technicolor Population: Has grey skin. Combined with his gaunt appearance, it makes him look like a zombie.
- Everyone Calls Him "Doctor"
- For Science!: Sells suspicious medicines at bargain prices as a ruse to have them tested.
- Idiot Hair
- Morally Ambiguous Doctorate: He sells his patients dubious medicines so that he can test them out. That's not at all suspicious.
- Rapunzel Hair: Reaches past his hips.
- You Gotta Have Purple Hair
The nurse who accompanies Doctor as support. Can't ever seem to insert a needle properly (although that might not be an accident).
- Amazing Technicolor Population: Also has grey skin. Taken together with the giant bolts sticking out from her head and the stitching across her face, she looks like Frankenstein's monster.
- Everyone Calls Her "Nurse"
- Frankenstein's Monster: Resembles him with the giant bolts sticking out of her head and the stitching on her face.
- Hand-Hiding Sleeves: From which multiple surgical implements emerge.
- Snake Oil Salesman: Occasionally tries to sell something to Zeabolos. Agree immediately and you get Snake Juice, an item that recovers all of your MP but is generally useless as you're should never let yourself run out of AP to have spent MP in the first place. Refuse and she forces you to buy anyway, but the item turns out to be Ultimate Extract instead.
A nemesis of the Fallen Ones and one of the four archangels that serve God. He fell into the Underworld, severely injured, but Elma has been nursing him back to health.
- All Men Are Perverts: Played with. While Ashmedia teases him a lot, he only really has eyes for Elma.
- Because You Were Nice to Me: He has a massive crush on Elma, the only denizen of Hell who really treats him well, and doesn't act as arrogant or abrasive to her as to the others.
- Butt-Monkey: Let's see, he falls into the Underworld due to severe injuries, it's implied that the other angels don't like him, he gets called trash and tossed around by the Overlords...
- Character Development: Gradually calms down and becomes a better person as the game goes on, courtesy of Elma. Unfortunately for him, she's capable of being killed by Trillion.
- Enemy Mine: He, and what's left of Heaven, gives all he can to help the Underworld in the war effort. While initially unappreciative, Zeabolos sees some of his own despair in the angel, and agrees.
- Green Thumb: He likes gardening and raising plants, and even breeds two new species of flowers to give to Elma in her ending.
- Master of None: His form of training offers a random, but above average increase to all types of experience, but at triple the normal fatigue cost.
- Idiot Hair: His halo circles around it.
- Small Name, Big Ego: He's been left terribly diminished by the destruction of the human world and the near-collapse of Heaven, but he's still quite arrogant. This often leads to him being bullied and pushed around by the Overlords.
The head maid who manages the maids that tends to the Overlords in Zeabolos' castle.
- Curtains Match The Windows: Blonde with gold eyes.
- Gossipy Hens: When the maids are found together when not working they're usually talking about the current Overlord.
- Little Bit Beastly: Has fox ears and a tail.
- Meido: Very reliable and experienced.
- Prim and Proper Bun
A maid that tends to the Overlords in Zeabolos' castle.
- Genki Girl: Described as very bright and cheerful. Sometimes she's a bit too cheerful...
- Gossipy Hens: When the maids are found together when not working they're usually talking about the current Overlord.
A maid that tends to the Overlords in Zeabolos' castle.
- Gossipy Hens: When the maids are found together when not working they're usually talking about the current Overlord.
- Little Bit Beastly: Has rabbit ears and a tail.
- Shrinking Violet: Generally timid and quiet. But when she wants to say something, she won't hold back.
- You Gotta Have Purple Hair