Devils are powerful beings that come from the Underworld. High-ranking Devils rule over other demons depending on their family's rank and prowess, and can have up to 15 "slaves", which are represented by each piece in a chess game (Rook, Knight, Pawn, etc.) which are called Evil Pieces. Most Pure Blood devils (all direct ancestors were born devils with no reincarnated devils 'thinning' the bloodline) are born with High-Class rank. Lower-ranking Devils (mostly devils who were reincarnated through Evil Pieces) are often looked down upon, and usually serve a Devil of higher authority. If a Devil were to divert away from his/her master (then on known as a "Stray Devil" (はぐれ悪魔,Hagure Akuma?)), they have to be captured or killed before they go out of control. The ranks of the Devils are spilt into Low-Class Devils (下級悪魔,Kakyū Akuma?), Middle-Class Devils (中級悪魔,Chūkyū Akuma?), High-Class Devils (上級悪魔,Jōkyū Akuma?), and Ultimate-Class Devils (最上級悪魔,Saijōkyū Akuma?). There are three ways for Low-Class Devils to increase rank: 1) Showing exceptional ability or skill in combat (rare even before Peace Treaty as everybody feared mutual annihilation if another war broke out,) 2) Have a high number of contracts completed and/or high quality rewards received, and the most common 3) Earn high points, reputation, and opinion in official Rating Games.
Four Great Maous (四大魔王,Yondai MaŌ?, lit. "Four Great Satans")
The Four Maous that lead the Devils. The current Maous are not the original ones, rather they received the names with the position. Therefore the names "Lucifer" and "Beelzebub" while used as names are more like managerial position titles. Sirzechs, for example, was born Sirzechs Gremory, but because he is a Maou he gave up the name Gremory and is always referred to as Sirzechs Lucifer. However his son Millicas doesn't inherit the name Lucifer but instead inherits his father's birth name of Gremory and thus is Millicas Gremory.
The 72 families of pure-blooded Devils. The families representing the 72 Pillars are: Bael, Agares, Vassago, Gamigin, Marbas, Valefor, Amon, Barbatos, Paimon, Buer, Gusion, Sitri, Beleth, Leraje, Eligos, Zepar, Botis, Bathin, Sallos, Purson, Marax, Ipos, Aim, Naberius, Glaysa-Labolas, Buné, Ronové, Berith, Astaroth, Forneus, Foras, Asmoday, Gäap, Furfur, Marchosias, Stolas, Phenex, Halphas, Malphas, Raim, Focalor, Wepal, Sabnock, Shax, Viné, Bifrons, Uvall, Häagenti, Crocell, Furcas, Balam, Alocer, Caim, Murmur, Orobas, Gremory, Ose, Amy, Oriax, Vapula, Zagan, Valac, Andras, Flauros, Andrealphus, Cimeries, Amduscias, Belial, Decarabia, Seere, Dantalion and Andromalius. Out of the 72, only 34 are still active after the war. Although some of the families listed as extinct because any of the members still alive aren't pure blooded devils, but had their blood mixed with other races for various reasons. For example, a couple of Sairaorg's servants' houses had married humans to help preserve their bloodlines.
Extra Demons (番外の悪魔（エキストラ・デーモン）,Ekisutora Dēmon?, lit. "Devil of Extra")
Houses of Top-class Devils who are not part of the 72 Pillars which consist of pure-blooded Devils. Currently, the only houses known are the House of Lucifuge, the House of Abaddon, the House of Belphegor and the House of Mephistopheles.
Angels are the powerful beings who serve God. They come from Heaven, and have the powers to inflict pain upon Devils due to their light-based powers. All Angels have white wings (golden wings for Archangels) and a halo above their head. After God died, the Angels were unable to increase their numbers until the creation of the Brave Saint system which reincarnate humans into Angels.
The leader of the Angels who died in the previous war. He is succeeded by the Archangel Michael in maintaining the "system" He left after His death. This was kept secret by the heads of all the factions due to fear of the chaos and increased chances of an attack by a foreign faction (essentially any non-Christian Parthenon such as the Norse Gods, Greek Gods, etc.)
A group of highest ranked Angels who are guardians of the Throne of Heaven. They are the ones that are maintaining the system used by the original God after His death in the war. The leaders of the Seraph are Michael, Gabriel, Raphael and Uriel.
Angels that have fallen from the grace of God due to having "impure thoughts" that divert from His teachings (e.g. the leaders of Grigori had sex with human women and had fallen as a result). Their appearances are similar to those of the Angels, albeit with black wings and lacking a halo above their head. Even though they have been cast out from Heaven, Fallen Angels have somehow retained the ability to use light-based weapons. However, they receive damage like Devils do if they pray to God.
An organization created by the Fallen Angels. Members include humans exiled from the Church and Sacred Gear wielders. The leaders of the Grigori are Azazel, Shemhazai, Armaros, Baraqiel, Tamiel, Penemue, Kokabiel and Sariel. Like Devils, they mainly live in the Underworld.
Dragons are one of the most prominent beings in High School DxD, as well as being one of the most powerful. The majority of Dragons do not align with any of the three factions. The most famous of the Dragons are the Five Great Dragon Kings (五大龍王,Godai RyūŌ?), Two Heavenly Dragons (二天龍,Nitenryū?), the Dragon God (龍神,Ryūshin?)Ophis, and the True Dragon (真龍,Shinryū?), Great Red. In Volume 14, another class of Dragons known as the Evil Dragons (邪龍,Jaryū?) was introduced and are known to be more powerful than the Dragon Kings.
Humans are not deeply concentrated on in High School DxD, but they do play an important role in the Devil's ranking system. Humans are also the only species that are born with the Sacred Gears. Normal humans that have learned magic from other religions/factions are known as Magicians (魔術師,Majutsu-shi?).
A group of supernatural monsters from Japanese folklore. There are many species of yōkai. Kunou and Yasaka are Nine-tailed Foxes (九尾の狐,Kyūbi no Kitsune?), while Koneko and Kuroka are Nekomata (猫又?, lit. "Forked Cats"), a sub-species of Bakeneko (化け猫?, lit. "Monster Cats"). Other types of yōkai include Yuki-onna, Kappa, Karasu-Tengu, and Nue. The ones shown so far are led by Yasaka in Kyoto. For Devils to visit, permission has to be requested ahead and special "tickets" given, allowing access to the various shrines and temples without feeling fear from Holy elements or receiving damage from traversing Holy Ground.
A race of supernatural creatures even more proud and aloof than Devils. While some Devils, particularly the Gremory clan, treat their slaves/servants like family or allow advancement in rank, while for a Vampire to be treated as High Class, they have to be born into a Vampire High Class Family. Transformed vampires are despised and eternally Low Class and none of the clans are considered to even be close to treating their slaves even remotely as family. Gasper is despised for being half human, his out of control Sacred Gear, and apparently the 'Darkness' Vampire Powers he used to defeat Georg. Like the stories tell, Vampires are weak against sunlight, garlic and holy items. Although Gasper's clan, the Vladi, have a clan trait of being Daywalkers, meaning sunlight won't kill or hurt them any more than it does Devils. Vampires are mostly cut off from other groups by preference, and word is that fighting between clans broke out shortly after one clan got hold of a Longinus user.
Khaos Brigade (禍の団（カオス・ブリゲード）,Kaosu Burigēdo?, lit. "Army of Disaster")
An organization created by Ophis, the Dragon God, with the sole purpose of removing the Great Red, the most powerful Dragon in existence known as the True Dragon, out of the Dimensional Gap. The Khaos Brigade consists of few races: Fallen Angels, humans, and a few (unfallen) Angels. However, Ophis is more of a figurehead used to attract followers or provide power boosting snakes and she has almost no direct role outside of providing snakes for anything unrelated to killing Great Red. Essentially she just sat in a room, provided snakes when asked, and did little else until Vali started talking with her. All the ideologies, missions, grand plands, and such not having anything to do with Great Red were created by and/or supported by the other members. The Khaos Brigade has several factions:
A faction of the Chaos Brigade led by Vali Lucifer. The members are Bikou, the descendant of the original Monkey King, Sun Wukong; Arthur and Le Fay, the Pendragon Siblings who are the respective descendants of King Arthur and Morgan le Fay; Kuroka, Koneko's older sister and a Stray Devil; Loki's son, Fenrir, and the Golem Gogmagog. Their main goal seems to be exploring, going on adventures, and finding strong opponents to battle.
Old Maou Faction (旧魔王派,KyūmaŌ-ha?, lit. "Old Satan Faction")
A faction of the Khaos Brigade consisting of descendants of the original Maous. They are the only group of Devils who resist using the Evil Pieces system, as they believe them to be a disgrace to Devils because they reincarnate Humans and other races into Devils. They are also against the Devils' current system, and seek to change it by overthrowing the current Maous. Vali Lucifer was part of the Old Maou Faction prior to him defecting and forming the Vali Team. The remaining leader, Shalba Beelzebub, was later defeated as of Volume 11 of the light novels, causing the Old Maou Faction to weaken. The remaining members were terminated by Ajuka Beelzebub in Volume 12.
A faction of the Khaos Brigade led by Cao Cao, the descendant of the ambitious ruler of China during the Three Kingdoms era. The faction is allied with Hades, the God from the Realm of the Dead, and it is also the most dangerous faction of the Khaos Brigade due to its members being Sacred Gear, Holy/Demon Sword, and Longinus wielders. The Hero Faction was defeated in Volume 12 when Indra sends the majority of its main members, Cao Cao, Georg and Leonardo to the Realm of the Dead, taking all of their Longinus from them. Siegfried died in battle while Jeanne and Heracles are captured.
Games played between Devils who have gained a peerage. The game takes the form of a strategic battle between the King and his/her pieces. It is fought on a map of their choosing, and can be a perfect replica of anywhere on Earth or in the Underworld. The Rating Game shares many similarities to the game of chess. Only matured Devils are allowed to participate in official Rating Games. The servants of the Devil with peerage are named after the pieces of chess: Queen, Rook, Knight, Bishop and Pawn. Only Devils with peerage can become the King piece. Participants are placed into four categories: Power, Technique, Wizard, and Support. Like the game of chess, the maximum numbers of players in a Rating Game is 16 and the team loses the game once the King is defeated. The Rating Game is created to measure a Devil's strength, which will reflect their social standing in the Underworld. In fact, the Rating Game is so famous that the top 10 rankers are considered as heroes to the Devils.
Dice Figure Game
A variant of the Rating Game with different mechanics. Instead of a long, full-team battle, it will be a blitz (short battle) with limited members. Both Kings will row a six-sided dice (one each) and the number added up from both Kings will determine the value of Pieces (servants) to be sent. However Kings are not forced to completely use all the points (with the total value of eight, Kings can send two Knights and have two left over), which will be wasted and not added to next roll. Servants that consumed two or more Pieces of its kind will have the added-up value of the Piece (a servant that has consumed two Pawn Pieces will have the value of two, or a servant that have consumed two Knight Pieces will have the value of six).
Scramble Flag Game
A variant of the normal Rating Game where the goal of the game is to collect flags scattered around the battlefield.
Based on the game of chess, a total of fifteen pieces (1 Queen, 2 Knights, 2 Bishops, 2 Rooks and 8 Pawns) are given to top-class Devils (King) with a peerage. These pieces are used to reincarnate other beings into Devils and become servants of the top-class Devil. The Evil Pieces were created by Ajuka Beelzebub to replenish the number of Devils after the Great War. Each piece has a corresponding value. These values are used to determine which piece may be used to reincarnate someone, their strengths, talents or skills play a role in determining their value. Different Evil Pieces cannot be used together. Evil Pieces can also be exchanged between top-class Devils with peerage. Unused Evil Pieces can undergo changes according to the master's growth, allowing the King to use less pieces when reincarnating humans into Devils. The Evil Pieces, however, are not completely omnipotent, as it cannot be used to reincarnate Gods, Buddhas and Dragon Gods into Devils.
Queen (女王,Kuīn?) - Worth 9 Pawns. Traits of Queens have all the characteristics of Rooks, Knights, and Bishops.
Rook (戦車,Rūku?) - Worth 5 Pawns. Traits of Rooks are immense strength and defense.
Knight (騎士,Naito?) - Worth 3 Pawns. Traits of Knights are increased speed and mobility.
Bishop (僧侶,Bishoppu?) - Worth 3 Pawns. Traits of Bishops are enhanced magical abilities.
Pawn (兵士,Pōn?) - Worth 1 Pawn. Traits of Pawns has the ability to promote into a Queen, Rook, Knight, or Bishop in enemy territory.
Aside from the Evil Pieces, there are also special pieces known as Mutation Pieces (変異の駒（ミューテーション・ピース）,Myūtēshon Pīsu?, lit. "Mutant Pieces"). If reviving a person requires 8 Pawns, then using 1 Mutation Piece would suffice to revive that person instead of using 8 Evil Pawn Pieces. Mutation Pieces can be a Queen, Rook, Knight, Bishop or Pawn. They are said to be very rare. It is also possible for a normal Evil Piece to become a Mutation Piece, as with the case with Issei after his supposed "death".
Brave Saint (御使い（ブレイブ・セイント）,Bureibu Seinto?, lit. "Royal Users")
Used by the Angels to resurrect other beings into Angels to increase their numbers. The Saint Cards are based on the Evil Piece system of the Devils, albeit being based on a suit of playing cards. The cards consist of 12 cards that represent the Twelve Apostles. And similar to the Evil Pieces, the Brave Saints also have their own special ability that are based on actual card games like poker and blackjack. Only people with a "pure heart" can become an Angel. There is a special type of card known as the Joker Card (ジョーカー,Jōkā?), whose function is similar to those of the Mutation Pieces.
The Brave Saint system is created by the Archangel Michael in Volume 6 by copying the Devils' Evil Piece System. This is so that the Angels can increase their numbers, as they cannot depend on God anymore following His death in the war.
Sacred Gears are special items created by the original God that certain people are born with. Sacred Gears carry different effects ranging from healing to battle-related effects; a Sacred Gear may only have one effect. It is said that many people who are recorded in history were possessors of a Sacred Gear. Only humans and half-humans may be born with a Sacred Gear. If the Sacred Gear is removed from their owner, the possessor will die. It is explained that the original God created the Sacred Gears as part of His system to enact miracles on Earth. As to why Angels and Devils are never born with them, yet keep them when transformed from humans, is another mystery. Artificial Sacred Gears can be made (as with the case with the Fallen Angels' leader Azazel), but are inferior to the real ones. It is possible for an individual to own more than one Sacred Gear, as with the case with Kiba.
Longinus (神滅具（ロンギヌス）,Ronginusu?, lit. "Tools that Destroy God")
The ultimate of the Sacred Gears, each having more than one ability compared to a normal Sacred Gear which only has one. There are 13 Longinus in total. The True Longinus, the first and ultimate Longinus, takes the form of a spear. It was the spear that St. Longinus used to kill Jesus Christ, and a single stab by it can kill and vaporize a high-ranking Devil instantly. It is currently owned by Cao Cao from the Hero Faction. The remaining Longinus are Zenith Tempest, Annihilation Maker, Dimension Lost, Boosted Gear, Divine Dividing, Regulus Nemea, Canis Lycaon, Incinerate Anthem (紫炎祭主による磔台（インシネレート・アンセム）,Inshinerēto Ansemu?, lit. "Chief Mourner’s Crucified Stand of Purple Flame"), Absolute Demise (永遠の氷姫（アブソリュート・デイマイズ）,Absoryūto Deimaizu?, lit. "Eternal Ice Princess"), Innovate Clear (蒼き革新の箱庭（イノベート・クリア）,Inobēto Kuria?, lit. "Miniature Garden of the Green Tree of Innovation"), Sephiroth's Grail and Telos Karma (究極の羯磨（テロス・カルマ）,Terosu Karuma?, lit. "Ultimate Karma"). Of the thirteen, only seven have appeared in the series so far.
The evolved form of the Sacred Gear. The Balance Breaker is the most powerful manifestation of all Sacred Gears. Once reached, the Balance Breaker can be entered again far more easily than the first time. With proper training, it can be maintained for a longer period of time. Balance Breakers can also have a sub-species, which are more powerful than the actual ones. The feelings of the possessor trigger this evolution.
Juggernaut Drive (覇龍（ジャガーノート・ドライヴ）,Jagānōto Doraivu?, lit. "Dragon of Supremacy")
A special ability of Sacred Gears with beings sealed inside them. Juggernaut Drive unleashes the true powers of the Sacred Gears but at the cost of its possessor's life. The Juggernaut Drive is exclusive to the Sacred Gears/Longinus, Boosted Gear and Divine Dividing. For other Sacred Gears that have creatures sealed inside such as the Regulus Nemea, their Juggernaut Drive goes under a different name called "Breakdown the Beast" (覇獣（ブレイクダウン・ザ・ビースト）,Bureikudaun za Bīsuto?, lit. "Beast of Supremacy"), but functions in a same way.
The ability to reverse the characteristics and capacity of various Sacred Gears. It is in the research stage, but the application of counter-based artifacts are risky to use.
Chaos Drive and Chaos Break
A special doping for Sacred Gears made from the blood of the original Maou, created by the Hero Faction with the help of the Old Maou Faction. The doping, called Chaos Break, allows the Sacred Gear to undergo Chaos Drive, in which the Sacred Gear fuses with the user while transforming the user into a monstrous form. The names are taken from the Balance Breaker and Juggernaut Drive.
A set of four legendary swords forged by the original God. A small scratch from a Holy Sword is enough to cause lethal damage to Devils and Fallen Angels alike. Only a select few have the capability to wield a Holy Sword. Holy Swords that are broken can be reforged as long as the core is intact, as shown in the case of Excalibur. It is also possible for two different Holy Swords to be fused into one. There are also the common Holy Swords known as the light sword that are wielded by normal exorcists.
One of the two Holy Swords wielded by the Legendary King of Heroes, King Arthur Pendragon, of Camelot. It was broken in the war long ago and reforged into seven swords through Alchemy and two of the blades were each stored by the Catholic Church Headquarter Vatican, Protestant Church, and Eastern Orthodox Church. In Volume 3 of the light novels, Kokabiel and his men stole an Excaliburs from each Church. Shortly after stealing Irina's sword, the four stolen Excaliburs were temporarily fused into one by Valper Galilei. The fused Excalibur (wielded by Freed Sellzen) was broken by the combined forces of Yuto's Sword of Betrayer and Xenovia's Durandal. The broken fragments were then retrieved by Irina Shido who took them back to the Church to be reforged. After becoming a Devil Xenovia returned her Excalibur to the Catholic Church as others could still use it while she was the only one who could wield Durandal. The Excalibur fragments were later fused into the Durandal as "Control Parts" (制御パーツ?) for Xenovia, who is still unable to fully master the Durandal, to help protect the Peace Treaty between the Angels, Devils and Fallen Angels from terrorists and outside forces.
Excalibur Destruction (破壊の聖剣（エクスカリバー・デストラクション）,Eksukaribā Desutorakushon?, "Holy Sword of Destruction")
A sword with the ability to unleash pure, destructive power that can easily shatter anything it comes into contact with. It was wielded by Xenovia. While powerful enough to shatter Yuuto's Demonic swords with one swing it still isn't at the level of Durandal.
Excalibur Mimic (擬態の聖剣（エクスカリバー・ミミック）,Eskukaribā Mimikku?, "Holy Sword of Mimicry")
A sword with ability to transform itself into any shape its user desires (for example, in Irina's hands, it becomes a katana) in battle, but worn as a bracelet when not fighting. However, it was reduced back to a fragment at the end of the Volume 3 in the Light novels and didn't reappear until it was shown as part of Durandal's control sheath.
Excalibur Rapidly (天閃の聖剣（エクスカリバー・ラピッドリィ）,Ekusukaribā Rapiddoryi?, "Holy Sword of the Heavenly Flare")
A sword that grants the user and blade enhanced speed.
Excalibur Nightmare (夢幻の聖剣（エクスカリバー・ナイトメア）,Ekusukariā Naitomea?, "Holy Sword of Dreams")
A sword that allows the wielder to cast illusions.
Excalibur Transparency (透明の聖剣（エクスカリバー・トランスペアレンシー）,Ekusukaribā Toransupearenshī?, "Holy Sword of Transparency")
A sword that allows the blade and/or wielder to become invisible.
Excalibur Ruler (支配の聖剣（エクスカリバー・ルーラー）,Ekusukaribā Rūrā?, "Holy Sword of Control")
A sword that grants the user the ability to control his/her opponent. It is the strongest Excalibur fragment.
Excalibur Blessing (祝福の聖剣（エクスカリバー・ブレッシング）,Ekusukaribā Buresshingu?, "Holy Sword of Blessing")
A sword that has the ability to temporarily grant others the ability to use Holy Swords.
A Holy Sword previously wielded by Saint George, the Dragon-killing Saint. Unlike the other Holy Swords, Ascalon specializes in killing Dragons, and is named the Dragon Slayer (龍退治の剣（ドラゴンスレイヤー）,Doragon Sureiyā?, Sword of Dragon Extermination). It was passed to Issei on Volume 4 by the Archangel Michael as a sign of peace between the three factions. However, members of each faction had to use various spells, alchemy and powers to allow Issei to wield and store it without being damage by the sword's Dragon Slayer attribute. The sword is usually stored in the Boosted Gear and can be summoned in battle. Issei, however, rarely uses the sword and mostly lends it to Xenovia during fights.
A Holy Sword that rivals the original Excalibur. It is currently wielded by Xenovia. It is a sword with destructive powers that cannot be compared. The former owner of the sword was the Paladin of the Holy Roman Emperor Charlamagne: Roland. Roland had used the sword to fight off a hundred thousand-strong army, thus evidencing his great strength and the reason Xenovia has yet to fully master the sword. The Durandal was later upgraded into the Ex-Durandal (エクスデュランダル,Ekusu-Dyurandaru?) using the remaining Excalibur fragments which functions as a form of sheath. The Excalibur fragments can also be temporairly separated and materialized as additional swords for Xenovia's use. Such as when she gave Excaliburs Transparency and Mimic to Rossweiss in volume 10 of the Light Novels. The Ex-Durandal was shattered in Volume 11 by Cao Cao's using one of the True Longinus' Seven Treasures, but was repaired and fully completed after gaining the final Excalibur fragment that was previously owned by Arthur Pendragon.
The other Holy Sword wielded by King Arthur. The Sword in the Stone known as the "Holy King Sword" (聖王剣,SeiŌken?). It is the most powerful Holy Sword to be created, possessing sharpness and destructive powers that surpasses even that of Excalibur and Durandal. It is currently owned by Arthur Pendragon, the descendant of original King Arthur.
Aside from the four listed, there is another Holy Sword called Ame no Murakumo no Tsurugi (天叢雲剣?, "Sword of the Gathering Clouds of Heaven") that is not forged by God but rivals the Original Excalibur and Durandal.
The opposite of the Holy Swords forged by the original Maou. They are the polar opposite of the Holy Swords, in which they use demonic powers. Demonic Swords are swords are said to be cursed and bring misfortune to its wielders.
The Sword of the Sun and the strongest Demon Sword known as the "Demonic Emperor Sword" (魔帝剣,Mateiken?). Gram is a Dragon Slayer sword with the destructive power of the Holy Sword Durandal but does not need to be charged to do destructive attacks. It was previously used by the original Siegfried to slay the Dragon King Fafnir (though Fafnir was later revived). However, unless its power is suppressed Gram will also cause severe damage to any wielder with Dragon attributes or is using a Dragon type Sacred Gear in Balance Breaker mode.
A Demon Sword that creates a variety of ice attacks. Such as huge pillars of ice from the ground, ice spears, or freezing attacks. Similar to Yuuto's Ice Sword abilities, but with the difference of a masterpiece by an expert like Hattori Hanzō and an intermediate blacksmith's (Yuuto) blade which, no matter how good, still shows there is more to learn and experience to gain.
All five Demon Swords (and one Holy Sword) were wielded by Siegfried of the Hero Faction until Volume 12 when Gram abandons Siegfried and chooses Yuuto as its new wielder. The remaining swords accept Yuto as its new owner after Siegfried died. It is possible for a Holy Sword to be used by a Devil, as with the case of Ascalon, Arondight and Durandal. Although the Devil either needs to already have an affinity (Xenovia with Durandal,) develop the affinity in some way (Yuuto absorbed Holy element and gained the Sacred Gear Blade Blacksmith,) have it temporarily passed to them by someone with the affinity (Xenovia did so to allow Yuuto to summon and wield Durandal,) or have a combination of magics, alchemy, and various powers used to alter the sword (Issei with Ascalon.)
The school where all the protagonists go to. It was previously an all-girls private school that turned into the coed school few years before the storyline. It is administrated by the Sitri Family in the day and the Gremory Family in the night. The known clubs in the school is the Occult Research Club (オカルト研究部,Okaruto Kenkyū-bu?) run by Rias Gremory, the Student Council (生徒会,Seito-kai?) run by Sona Sitri, the Tennis Club (テニス部,Tenisu-bu?) run by Kiyome Abe, and the Kendo Club (剣道部,Kendō-bu?).
The house of Issei Hyodo and his parents, which later became the house for the girls of the Occult Research Club. Originally a two-story terrace house, it was renovated in Volume 5 to a six-story building with three basement floors. Following the house's renovation, it also has more than twice the land area after buying the lands of their neighbors.
The home of the Devils and Fallen Angels. It has the same size as the human world but has a much larger landmass, as there are no oceans. The sky is purple at both day and night. The Underworld was originally split into two regions: The Devils' Region and the Fallen Angels' Region, which ended in Volume 4 after the creation of the peace treaty between the leaders of the three factions.
The capital city of Devils in the Underworld.
The former capital of Devils in the Underworld under the Old Maou regime.
The Power of Destruction is a power exclusive to the Bael Family that is called the Great King and is the highest-ranking among the 72 Pillars. The Gremory siblings – Sirzechs and Rias, inherited this ability from their mother Venelana who was from the Bael Clan.
Light-Based Powers (光ベースのパワーズ,Hikari-Bēsu no Pawāzu?)
An ability that is used by Angels and Fallen Angels. It is primarily used to create light-based weaponry, the most common being light spears.
The power to control the flow of life. By controlling the flow of ki a person can strengthen physical bodies or cause vegetation around them to bloom or to wither. Knowing Senjutsu allows the reading of ki and auras and to spy on the target's state from afar. Disrupting the opponent's ki or severing it can cause direct damage to living things. There are very few ways to defend against Senjutsu. It is said that upon full mastery of Senjutsu, the user can manipulate time and space.
One weakness of Senjutsu is while it can read and handle spirit energy, it also takes in the malice and ill will that floats in the world and absorbing too much malice will result in one being drunk on power.
Koneko has stated that Bouchuujutsu, a.k.a. Lovemaking Technique, a.k.a. having sex, is the best way to utilize Senjutsu's healing properties as it allows the user's ki to merge and strengthen the recipient's ki.
A type of energy a person obtains by training their body to the uttermost limits, gaining the base of life itself and wearing it around their body, giving them destructive attack power. A person trained in Senjutsu can also use Touki. The sole exception to this is Sairaorg Bael, who obtained his Touki by body training alone.