The Dark Rebel Army is B/N's faction which mostly consider of monsters, Demi-humans, Blades, and dark wizards. There is also a Dark Guild formed by B/N and Arkham known as Devil Hand. 

B/N: (leader)

Malos: (second-in command, B/N's Blade)

Akhos: (strategist)  

Patroka: 

Mikhail: 

Nia: (formerly at the end of B/N's Arc) 

Dromarch: (Nia's Blade, formerly at the end of B/N's Arc)

Sever: (B/N's other Blade) 

Obrona: (Akhos' Blade) 

Perdido: (Patroka's Blade) 

Cressidus: (Mikhail's Blade) 

Arkham/Jester: A dark wizard who is obsessed with the Legend of Sparda and Lady's father. 

The Four Divine Kings: a squad of powerful individuals chosen by B/N. 

Kall-Su: The Frost Wizard. B/N's right-hand man and best friend. A formidable sorcerer who yields ice magic, his powers are equal to that of Zeref. 

Gara: A ninja master who wields the Murasame Blade and leads an army of thousands of dark ninjas. Though tough and free-spirited, he is manly and takes good care of others. 

Arshes Nei: The Empress of Thunder. A half-elf born to a human and Dark Elf. Known as the "Thunder Empress," she is a magic swordsman who casts lightning spells. A war orphan picked up by Sparda, she was once like his daughter. But now she is an adversary, being one of the Four Divine Kings of the Dark Rebel Army. 

Abigail: A dark cleric known as the "Prophet of the Underworld," Abigail is one of the Four Divine Kings of the Dark Rebel Army. He uses sorcery to control his "Rotten Army" of undead beings. 

Three Sorcerer Generals: Three high ranking sorcerers within Arshes Nei's army.

Sean Ari: One of the Three Sorcerer Generals who makes spiders appear with her talismanic magic. Under orders from Nei, she is out to assassinate Y/N. She doesn't have much experience with men, and she is loyal and has a pure heart.

Kai Harn: One of the Three Sorcerer Generals. She casts Ancient Language Spells that turn her enemies into stone. Like Nei, she uses the orthodox sword techniques of the Hariken School and is a proud magic swordsman. She despises men and believes in the strong bond of the Sorcerer Generals. Under Nei's orders, she takes on Y/N. 

Di-Amon: One of the Three Sorcerer Generals, Di-amon is a muscular immortal vampire. He is a "True Forefather," making him the most powerful immortal in existence. In order to exceed Nei and Kall's powers, he collects the blood of virgins. His appearance is marked by his bulging muscles and gaudy makeup.

The 12 Sorcerer Shogun: An elite group of warriors serving Kall-Su.

Yngwie von Mattström: A calm and noble swordsman. He is one of the most powerful warlords of the Sorcerer Shogun, and his devotion to Kall-Su is particularly strong. His special technique, the Banisher of Night Emperor Sword, which he performs with his Shu Tora Sword 《Strad》, is a blow of such speed that it appears to ordinary people as a momentary flash of light. Hence, he is known as the user of the "Speed of Light Strike". 

Zion Sol Vanderverg: One of the Sorcerer Shogun. A mage equipped with the Black Renegade, an armour forged with negative power, and the《Soul Eater》, a black demon blade. He seems to have a history with a certain samurai...

Maclalpine Toni Strauss: A Demonic Garrotter who manipulates specially forged metallic threads called Demonic slicing threads. These threads cut through everything and can stretch for kilometres, so they can be stretched in all directions to form wards. He also uses the Garian Sword, the sword of sinners that dissipates magical defences. He is a victory supremacist who also favours cunning methods. 

Shella E. Lee: The last one to join the Sorcerer Shogun. She is a bard and by casting the nature magic, the claws of her hands become magic claws that can cut through rocks. The music she plays on her lyre brings confusion and death to those who listen to it. She is looking for a messiah to save the world, which is in turmoil like hemp, and believes it is Kall-Su... 

Ba Thory: A polymancer who keeps hundreds of millions of bugs inside his body. The types of bugs he carries in his body are diverse, including regenerating bugs that repair themselves and blood-sucking bugs as well as bugs that strengthen his own abilities such as sensing and augmentation. Like Macapine, he sees Yngwie、the first of the Sorcerer Shogun, as his rival. He is also characterised by his hot and bitter behaviour. 

Ran Di Rhodes Shutein Neubauten: A swordsman from a mercenary background, his main weapon is the Fire Whip. He and his close friend Yngwie are said to be the best of the Twelve Sorcerer Shoguns in terms of skill. He is the only one of them with a shield. He is said to have a history with Kai Harn and Sean Ari.

Sykes Von Snowwhite: Scholarly mage. He has a thirst for knowledge and is erudite, but also has a nervous disposition. He carries a rapier, but his main method of attack is to create a fault line in space with his sword and cut through the target, which cannot be protected by armour or shield. He follows Kall-Su out of his own ambition.

Ida Deesna: His class is the Demon World Illusionist. Also called Summoner because he is able to summon creatures from the demon world with two crystal balls from his waist. His weapon of choice is the Iron Fan, and he is characterized by his large physique and the make-up on his face, which is not unlike that of a summoner. 

Zakk Walder: A martial artist who has mastered the legendary fighting martial art known as Karate, he is capable of unleashing hundreds of fists per second. His weapon of choice is the Sonic Sword, a pair of small swords with two blades that reach the speed of sound. Along with Shella, he is the youngest of the Sorcerer Shogun.

Bol Gil Bol: A shadow master from a remote tribe who has inherited the magical power to manipulate shadows at will. He has the temperament of a warrior who recognises the strength of even his enemies. He wears black armour with sharp knife-shaped spikes and carries a poison sword as his weapon.  

Vlad Kills: He boasts a massive frame of nearly three metres and wears a huge chainmail and full plate armour. With his monstrous strength, he wields a weapon that is a combination of a warhammer and a greataxe. Because of the way he fights, he is nicknamed a walking tank, despite being a knight.

Ross Zaboss Friedrich: A magical swordsman who uses gravity to crush opponents with his sword, and is one of the Sorcerer Shogun. 

Seven Deadly Sins: Seven elite fighters of Devil Hand guild as well as the keys to unlock Temen-ni-gru instead of the demons originally sealed within the tower. These Dark Wizards each have their own unique power which fits with their sin. 

Iblis: The leader and Strongest of the Seven Deadly Sins, she wields Morning Star Magic, a hybrid of Light and Darkness Magic. She represents the sin of Pride.

Mammon: A dark wizard who represents the sin of Greed because he wields Gold-Make Magic, which he can make gold and can melt it into a hot liquid.

Asmodeua: A dark wizard who represents the sin of lust with Spider-like magic powers.

Belphegor: A dark wizard who represents the sin of Sloth. Instead of fighting himself, he uses Legion magic where he uses Drones to fight for him.

Satan: A dark wizard who represents the sin of Wrath. He uses some kind of magic where when enemies hurt him, he becomes stronger. 

Leviatha/Sheeree: A dark wizard that represented the sin of Envy in the Devil Hand. Sheeree wields Magical Drain, Caster-type Magic that allows her to copy other people's magic for her own.

Beelzebub/Adrian: A child cursed by Wendigo Takeover, which gives him a never sating hunger. He represents the sin of Gluttony.

Three Brothers: The Three Brothers are animalistic demons from Devil Hand. 

Cragnar: A Lizard/Crocodile demon that attacks Natsu and Lisanna in an attempt to capture Lisanna. 

Ravairy: A raven demon. 

Fangor: A shark demon. 

Other members of the Dark Rebel Army: 

Osborn: A dark wizard who lived over 200 years. 

Kevidub: A Hydra summoner in service of Kall-Su. 

Dog: A werewolf in service of Di-Amon. 

Jodoh: A vampire servant of Di-Amon. 

Marron and Pierron: Werewolf and Weretiger bodyguards of Di-Amon. 

Doshi: A necromancy serving Abigail. 

Lynch: The ultimate undead soldier, with a near immortal body, and the leader of the army of decay. Doshi made him from only the finest chunks of one hundred dead warriors, and knights, using magic. He also wears the Demon-Mail, a suit of armor impervious to most physical and magical attacks.

Vivian: A "U-Type" undead flesh weapon, he was created by Doshi by implanting cells from a demon lord to a cyclops body. It retains all the abilities of a normal cyclops, but has the additional ability of being near immortal. Vivian carries the Devil Mace, a giant mace capable of creating earthquakes, and draining energy from the world around it. 

Lich: One of the Four Eddies master of the undead, and the most powerful member of Abigail's undead legion. He also possesses Satan's Ring, a magic ring capable of taking in the energy absorbed by the Devil's Mace to empower the wielder, and opening up portals into other dimensions that suck up everything around them. 

I hope you guys like B/N's faction, most of them are characters from Xenoblade 2 and Bastard, while some are OC characters. 

If you want to add characters from the heavy metal and dark fantasy anime into this book, let me know at the comments below. Peace out and enjoy!