Ainz Ooal Gown is formerly known as Momonga. He is the guildmaster of Ainz Ooal Gown, Overlord of the Great Tomb of Nazarick, and the creator of Pandora's Actor. He is regarded as the highest of the Almighty Forty-One Supreme Beings by the NPCs of Nazarick.
In the New World, he is the Sorcerer King of the Sorcerer Kingdom and the most powerful magic caster in the world. His other identity is famously known as "Momon," a dark warrior and leader of Darkness, an adamantite ranked adventurer group of that nation. Ainz Ooal Gown has the appearance of an Overlord, an undead skeleton creature who is devoid of skin and flesh. He tends to mainly wear an elaborate, jet-black academic gown adorned with golden and violet edges. When he has no clothes on, his whole body alone is purely made up of just his bones. He also has a dark red orb floating under his ribs that emanates a feeling of dread.

Albedo is the Overseer of the Guardians of the Great Tomb of Nazarick. She is in charge of the general management and supervision of the activities done by the seven Floor Guardians, meaning that she ranks above the other NPCs in Nazarick. She is the middle sister of the older sister Nigredo and younger sister Rubedo. Along with her sisters, she was created by Tabula Smaragdina. An impeccable beauty, Albedo is a woman with lustrous jet-black hair and the face of a goddess. She has golden irises and vertically split pupils; on her left and right temples are two thick horns protruding crookedly, and on her waist are a pair of black angel wings.
Albedo wears a pure white dress with silky gloves covering her slender hands and a golden spiderweb necklace that covers her shoulders and chest.

Shalltear Bloodfallen is a true vampire and the Floor Guardian of the first to third floors in the Great Tomb of Nazarick. She was created by Peroroncino. Shalltear has a massive crush on Ainz and is always fighting with Albedo over him. Shalltear is a vampire of short stature and has the appearance of a buxom fourteen-year-old girl. Described as a true beauty, she has pale shiny skin, seductive crimson-red eyes, and fine facial features. Shalltear's silver hair is tied in a ponytail through a large ribbon on top of it all, allowing others a full view of her face.

Demiurge is the Floor Guardian of the 7th Floor of the Great Tomb of Nazarick, the Commander of the NPC defenses, and the 2nd in command of the Floor Guardians. He is the creation of Ulbert Alain Odle. Demiurge is described to be a tall demon with dark skin and nicely combed black hair. Behind the round glasses are eyes so squinted that they are not normally visible. Wearing a British suit with a tie, he is dressed like a gentleman. Behind his back is a silver tail, covered with metal plates and six long spikes at the end.
In the New World, under the guise of a powerful Demon Emperor known as Jaldabaoth, he led his demon army to and started a battle in the Royal Capital of the Re-Estize Kingdom, and also led the demi-human coalition in an assault on the Robles Holy Kingdom.

Cocytus is a Floor Guardian of the 5th Floor in the Great Tomb of Nazarick. He is the creation of Warrior Takemikazuchi. Having an enormous body size of 2.5 meters, Cocytus has the appearance of an insect walking on two feet - a fusion between a mantis and an ant. With a tail twice as long as his height, Cocytus is covered in sharp spikes like icicles and has a strong jaw that can easily snap people's hands.

Aura Bella Fiora is a dark elf and one of the twin Floor Guardians on the 6th Floor in the Great Tomb of Nazarick. She is the older twin sister of Mare Bello Fiore and was created by Bukubukuchagama. As a beast tamer and ranger, she is capable of controlling magic beasts and is a master of guerrilla warfare. Aura is a boyish looking child with dark skin and pointed ears, a signature trait of the dark elves. She has golden hair and heterochromia, her left eye blue and right eye green. She wears reddish-black dragon scale leather covered by a white and gold vest embroidered with the sigil of Ainz Ooal Gown. Below it, she has a matching set of white trousers and gold plated shoes, and around her neck is an acorn necklace emitting golden light. She is equipped with a whip around her waist and a giant, decorated bow on her back.

Mare Bello Fiore is a dark elf and one of the twin Floor Guardians on the 6th Floor of the Great Tomb of Nazarick. Mare is the younger twin brother of Aura Bella Fiora. Alongside his sister, he was created by Bukubukuchagama. Mare is a child with dark skin and pointed ears, a signature trait of the dark elves. He has golden hair and heterochromia, his right eye is blue and his left eye is green. He wears a blue dragon scale leather full-body suit, covered by a white and gold vest embroidered with the sigil of Ainz Ooal Gown and a forest green-leaf cloak. Below, he has a matching short white skirt exposing his thighs, and on his neck is an acorn necklace emitting silver light. His slender hands are donned with shiny white silk gloves and he wields a twisted black wooden staff.

Victim is a Floor Guardian on the 8th Floor of the Great Tomb of Nazarick. Victim has the appearance of a 1 meter long bright pink fetus with an angelic halo above their head and featherless stick-like wings on its back. They does not have a neck of their own. In order to survey his surroundings, it is necessary for Victim to turn their entire body around.

Gargantua is the 4th Floor Guardian of the Great Tomb of Nazarick. Unlike the other Guardians, it is not a Custom NPC but a bonus won by Ainz Ooal Gown. Gargantua is an ultra-large, stone golem with a height of over 30 meters.

Sebas Tian is the head butler of the Great Tomb of Nazarick with several manservants and other butlers under his command. He was created by Touch Me. He is also the leader of the Pleiades Six Stars. Although he is not one of the Floor Guardians, his power closely rivals theirs. In a way, he is independent of their chain of command. He originally served as Nazarick's last line of defense alongside the Pleiades on the 9th Floor, to give time for the guild, Ainz Ooal Gown, to prepare for their final stand in the Throne Room. In his human form, Sebas Tian has the appearance of an elderly butler and he is dressed gracefully in his traditional black uniform. Sebas' hair is entirely white, just like his immaculate beard. He has visible wrinkles on his hollow face, which makes him seem gentle in appearance, but his eyes are as sharp as an eagle's.

Pandora's Actor is an Area Guardian of the Treasury and the financial manager of Nazarick. He is responsible for the upkeep of Nazarick and Ainz Ooal Gown. He was created by Momonga himself. Pandora's Actor's hat bears the crest of Ainz Ooal Gown, while the uniform he wears is very similar to the uniforms used by Neo-Nazi elite guards during the Euro-Arcology Wars 20 years ago. While Pandora's Actor is dressed in a yellow Neo-Nazi-esque uniform, he is just an egghead with no distinct facial feature except the three holes protruding on his face.

Narberal Gamma is a doppelgänger battle maid and a member of the "Pleiades Six Stars," the battle maid squad of the Great Tomb of Nazarick. She was created by Nishikienrai, one of the original nine founders of Ainz Ooal Gown. She is also known as Nabe, a magic caster and Momon's adventurer partner of Darkness. As an adamantite ranked adventurer, she is one of the most powerful adventurers in the Sorcerer Kingdom. Narberal Gamma is described as an elegant, snow-white skinned, black-pony tailed beauty. People believe her beauty is comparable to that of the Golden Princess. She wears a white bonnet in place of a helmet, and black armor decorated in gold and silver in the likeness of a maid uniform. As a battle mage, her weapon of choice is a golden staff plated in silver. In her adventurer persona, she wears a plain brown cloak.

Yuri Alpha is the vice-captain of the "Pleiades Six Stars," the battle maid squad of the Great Tomb of Nazarick. She was created by Yamaiko, one of the three female members of Ainz Ooal Gown. Yuri Alpha is a beauty with an intelligent look, wearing glasses and a blue-collar around her neck, most likely to keep her head attached to her body since she is a Dullahan. She wears her hair tied into a low-cropped bun at the back of her head. Lacking a metal plate in front of her skirt, her dress emphasizes mobility rather than defense. She is equipped with spiked gauntlets.

Lupusregina Beta is a werewolf battle maid and a member of the "Pleiades Six Stars," the battle maid squad of the Great Tomb of Nazarick. She was created by Beast King Mekongawa. Lupusregina Beta is a brown-skinned beauty with an athletic look and red hair tied in two long braids. She wears a maid uniform with short sleeves and long black gloves with a skirt that has a long slit on its left side, revealing thigh-high white stockings. She is equipped with an imposing black and silver scepter slung across her back.

CZ2128 Delta AKA "CZ" is an automaton battle maid and a member of the "Pleiades Six Stars," the battle maid squad of the Great Tomb of Nazarick. She was created by Garnet. CZ Delta is a girl who is short in stature and has red-gold straight long hair. She wears an eyepatch over her left eye, while her right eye has an emerald color and target-mark on the pupil. Her face is very delicate, it looks as if it was artificially crafted by hand. She wears accessories with military camouflage patterns. While her face is beautiful, she does not show her emotions and talks in a flat tone.

Solution Epsilon is a slime battle maid and a member of the "Pleiades Six Stars," the battle maid squad of the Great Tomb of Nazarick. She was created by Herohero. Solution is a blonde beauty with spiral curls and blue eyes, and clothing that emphasizes her sex appeal. The top of her maid uniform is designed to open easily, so Solution can absorb victims into her body. She is said to rival the most beautiful woman in the Re-Estize Kingdom, the Golden Princess.

Entoma Vasilissa Zeta is an arachnid battle maid and a member of the "Pleiades Six Stars," the battle maid squad of the Great Tomb of Nazarick. She was created by Genjiro. Her true form is that of an arachnoid, a spider-human hybrid. What acts as her "face" when disguised as a human, is actually an insect in the shape of a mask of a human face. Her hair seems to be rolled centipedes.

Great Tomb of Nazarick is the guild headquarters of Ainz Ooal Gown, widely renowned for being an unconquerable dungeon throughout YGGDRASIL. All klmaids and guardians reside here. The exterior shown outside the dungeon depicts the Great Tomb of Nazarick as being 200 meters wide in all four directions. It is enclosed by 6-meter tall perimeter walls surrounding the tomb, with two entrances being the front and back gates.

These floors are the Catacombs. They consist of the subterranean burial chambers where several dozen undead wander around in the darkness. These floors are guarded by Shalltear.

This floor is an underground lake located within a cavern. In the past, before Ainz Ooal Gown's conquest of the tomb, the boss of this floor was a giant white bat. Gargantua is the guardian of this floor.

This floor is a wide area filled with numerous icebergs. Weather phenomena, including cloud and snow, are present here. There used to be an area penalty that caused slow and inflicted ice-type damage, but it was turned off to save costs on maintenance after the teleportation. Cocytus is the guardian of this floor,.

This floor is about 200 meters in height. Created by Blue Planet, a fake sun , as well as a fake sky, exists on the ceiling, reproducing the day and night cycle that changes according to the time of day. There is no weather except the wind produced in this area, so Mare occasionally summons rain. Mare and Aura are the guardians of this floor.

This floor contains crimson lava flowing like a river, with numerous bubbles in these currents bursting as they reach the surface. This place, which is thoroughly inimical to the living, perfectly fits the description of a "hell world." In the past, before Ainz Ooal Gown's conquest of the tomb, the boss of this floor was a lightning breathing dragon. According to Demiurge, this dominion was designed and created for him by Ulbert Alain Odle, so it contains everything he needs to perform his function. Demiurge is the guardian of this floor.

This floor is Nazarick's final defense line, guarded by the most powerful NPCs. Capture of the 8th Floor means that Ainz Ooal Gown's chances of victory are low. This floor seems to be dangerous even to the NPCs of Nazarick as Ainz forbids them from entering the 8th Floor; at least one World Item exists here. Victim is the guardian of this floor.

This floor contains Guild Members' and NPCs' rooms. It also includes imitations of large communal baths, cafeterias, beauty salons, clothing stores, grocery stores, fitness salons, nail salons, and numerous other types of facility rooms. These facilities were originally just for decoration in YGGDRASIL, but they become real after the base's arrival in the New World. According to Ainz, it is arguably the floor with conditions most similar to that of the real world.

This floor contains the throne that the guild master Momonga sits on. The throne is a World Item better known as "The Throne of Kings." Albedo is the guardian of this floor.

This place is spatially isolated from other areas, so a Ring of Ainz Ooal Gown is necessary to enter the Treasury. On the other hand, the air in the Treasury is toxic and thus, anyone without poison immunity or items granting it will die within three steps. Pandora is the guardian of this floor.

New World is considered the tentative name of the unknown world, where the Great Tomb of Nazarick was supposedly transported to. Currently, the true name of this world is unknown.

Most of the spells derived from this magic in the New World are ranked by tier, like in YGGDRASIL. However, 6th tier or below is the only thing the world's natives have knowledge or use of as most of them had never heard of those ranking above it except a few like Evileye. Tier Magic was said to have been used by the Six Gods six hundred years ago. When the Eight Greed Kings arrived a century later after the previous group of players, they were able to effectively spread the existence of Tier Magic to the point that people began acquiring it and learning it over their traditional magic system.

According to Fluder, Wild Magic was supposedly looked upon as the primal magic of the New World before modern Tier Magic from YGGDRASIL was introduced. At present, the scarcity of users remains extremely small in numbers due to how difficult it was to cast as well as the following conditions required to use it like a Dragon Lord's bloodline, etc.

Prior to the introduction of Tier Magic into the New World, Runecraft was considered the original magical art used by dwarves in the past. However, it was viewed as outdated later on when Tier Magic was proven to be more superior in terms of magical enchantment effectively.

Exclusive to the New World, martial art skills allow the user to move in ways, which are normally physically impossible. So far, it can only be learned by natives born within that world.

Talent is a kind of innate ability that 1 in 200 can get in the New World. The talent's worth can be varied depending on the user's ability, job, circumstance, etc.

Slane Theocracy is a human nation of the New World and one of the three nations that neighbors Nazarick. One of the strongest countries in the region; it is a highly religious state, promoting human supremacy.

Sorcerer Kingdom is a newly founded nation in the New World. It is ruled by Sorcerer King Ainz Ooal Gown, who is attempting to turn it into a utopia for all races. While starting out as a land-locked city-state, it is continuously growing stronger and expanding territory, resources, and influence with each new conquest.

Re-Estize Kingdom was a human nation in the New World with an estimated population of nine million and one of three nations neighboring Nazarick. It was a failed state, suffering from near-constant political disorder and civil unrest.

Roble Holy Kingdom is a human nation in the New World, neighboring the Re-Estize Kingdom, that used to periodically face invasion from the neighboring Abelion Hills. Following the most recent invasion, the country's governmental and religious institutions were secretly taken over by the Sorcerer Kingdom.

Baharuth Empire is a human nation in the New World and one of the three nations neighboring Nazarick. Once one of the strongest nations in the region, they willingly became a vassal to the Sorcerer Kingdom upon witnessing the latter's overwhelming military strength compared to their own.

E-Rantel is the capital city of the Sorcerer Kingdom, inhabited by humans and directly governed by the Sorcerer King Ainz Ooal Gown. It was formerly a fortress city under the domain of the Re-Estize Kingdom ruled by the King.

YGGDRASIL was a fictional online game in the Overlord series. It was a DMMO-RPG (Dive Massively Multiplayer Online Role Playing Game) developed in Japan.

There were only two hundred of these items in YGGDRASIL. Even Guild weapons and Divine-class weapons couldn’t match them. World Items are the most powerful items admired and feared by players in the game. Given their rule-bending powers, in addition to the slim chance of finding them, a player who is lucky enough to come into possession of even just one of the World Items could easily shake the game's power balance. Basically, they are the "Wild card" or the "Joker card" of YGGDRASIL.

The World Champion was a special class granted only to the victor of the official martial tournament. Only a few had managed to obtain the World Champion class of which there were only nine in YGGDRASIL. As for the prize, the champion was given one piece of special equipment by the administrator. The power of this prized equipment surpassed Divine Class items, rivaling even Guild weapons. Of course, since it was a reward for the winner of the tournament, only the World Champion could equip it.

YGGDRASIL's weapons — Guild Weapons and a few others aside — possessed a data capacity that was determined by the value of the materials used in their construction and the skill of their maker. This data capacity limited the number of data crystals which could be added to it. Thus, rarer metals are allowed for the creation of a correspondingly more powerful guild weapon.

YGGDRASIL magic items were created from embedding computer data crystals. For instance, player-made items in the game could have their abilities changed by using data crystals.

Artifacts are not related to specific ranks. It just means they are items with fixed data and stats created by the game developers. Therefore, artifacts with low rank to high rank powers can exist. Dropped artifacts cannot have its original name be changed or customized by players unlike most items in the game. Nonetheless, artifacts are regarded to be the highest class of magic items out there excluding World Items.

Touch Me is one of the original founders of Ainz Ooal Gown and one of the strongest warriors in YGGDRASIL. He is the creator of Sebas Tian. He was also once the clan leader of the Nine's Own Goal before rebranding the guild into the creation of Ainz Ooal Gown.

Nishikienrai is a guild member of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the creator of Narberal Gamma.

Warrior Takemikazuchi is a guild member of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the creator of Cocytus.

Amanomahitotsu is one of the original founders of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the creator of Shihoutu Tokitu and the Chief Blacksmith.

Bukubukuchagama is one of the three female guild members of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. She is the older sister of Peroroncino and the creator of Aura Bella Fiora and Mare Bello Fiore.

Heroherois a guild member of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the creator of Solution Epsilon and one of the creators of the Homunculus Maids groups that work in Nazarick.

Ulbert Alain Odle is a guild member of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the creator of Demiurge.

Peroroncino is a guild member of Ainz Ooal Gown and is regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the younger brother of Bukubukuchagama and the creator of Shalltear Bloodfallen.

Tabula Smaragdina is a guild member of Ainz Ooal Gown and regarded as one of the Forty-One Supreme Beings by the NPCs of the Great Tomb of Nazarick. He is the creator of Albedo, Nigredo, and Rubedo.

Gazef Stronoff was the Warrior Captain of the Re-Estize Kingdom and King Ramposa III's personal bodyguard. He met Ainz at Carne Village and developed a mutual respect for him.

Brain Unglaus was a mercenary turned warrior of the Re-Estize Kingdom. Although initially somewhat arrogant, after barely surviving an encounter with Nazarick's denizens, he was set on a path to becoming a far humbler man.

Climb is the former bodyguard of Princess Renner of the Re-Estize Kingdom. Owing his life to her for taking him in when was living on the streets, he served the princess with unwavering loyalty, oblivious to her true nature.

Renner Theiere Chardelon Ryle Vaiself is a human turned Imp and the former Third Princess of the Re-Estize Kingdom. While publicly known as the "Golden Princess," she is actually a yandere infatuated with her bodyguard, Climb.

Enri Emmot is the Chieftain of Carne Village and the older sister of Nemu Emmot. She is the wife of Nfirea Bareare and General of the Goblin Army.

Nfirea Bareare is a famous pharmacist in E-Rantel. He is the grandson of Lizzie Bareare and the husband of Enri Emmot.

Jircniv Rune Farlord El-Nix is the current Emperor of the Baharuth Empire, also known as the "Bloody Emperor" for his violent purge of the nobility. Upon learning of Ainz, he intended to turn him into his pawn, until he learned of his true nature.

Jaldabaoth was a persona crafted by Demiurge in order to further his goals while hiding his relation to Nazarick. While initially playing the role himself, he later passed it on to a summoned Evil Lord Wrath.

Nazarick regards the members of the guild as the Supreme Beings, existences that rivaled gods. All of Nazarik worship them and give them their undying loyalty, the floor guardians would gladly lay down their lives in order to protect the supreme beings.