Faustian

Faustian
It is said that the first demons were bound by the mages of Hexania, but it was Ramdrant that perfected the art. While nearly any mage can bind a fiend with mystic chains, a Drantish archmage discovered that such contrivances were often unnecessary. With a silver tongue and promises of mystical rewards, the mage's students took his name for the title of their order, bartering a sliver of their power for the aid of all manner of creatures.

Dark Pact
The power of a faustian lies in the fiends they call to their side - unholy creatures with strange powers at their beck and call. Beginning at 8th level, at the end of any short or long rest, you can summon one of the following fiends. You can have only one such fiend summoned at a time, and it lasts until slain, dismissed as an Action, or until you fall unconscious. The fiend has its own compliment of actions, and acts on your initiative. As a bonus action, you can grant your summoned fiend Fel Might, which it can expend to enhance its action. The fiend uses your proficiency bonus, which it adds to attack rolls, damage rolls, AC, and saves. Each fiend has hit points equal to four times your level. Finally, if you have the Pact of the Chain class feature, you can use your summoned fiend as your familiar. If you do so, it is no longer restricted to Aiding you with skills of a single ability score, and can Aid you twice per short rest rather than once.
 * Flame Imp [Str 6, Dex 14, Con 12, Int 12, Wis 12, Cha 16]: A flame imp has a base AC of 13, is a Small creature, and has a walking speed of 30'. As an action, a flame imp can hurl an orb of hellfire at a target within 60' as a cha-based ranged spell attack. On a hit, the target takes 1d10+Cha fire damage. By expending its Fel Might, the flame imp can instead deal Xd10+Cha fire damage with attack, and half that damage to creatures adjacent to the target, where X is the number of damage dice used by cantrips at your level.
 * Void Beast [Str 16, Dex 8, Con 16, Int 10, Wis 12, Cha 10]: A void beast has a base AC of 15, is a Medium creature, and has a walking speed of 30'. In addition, it has Resistance to physical damage. As an action, it can rake a foe with claws of shadow as a str-based melee weapon attack. On a hit, the target takes 1d6+Str necrotic damage. This attack can also be used as a reaction, if an attack of opportunity is provoked. By expending its Fel Might, the void beast can instead deal Xd6+Str necrotic damage with attack and force the target to suffer disadvantage on attacks against creatures other than the void beast until the end of the void beast's next turn, where X is the number of damage dice used by cantrips at your level.
 * Mana Hound [Str 12, Dex 16, Con 12, Int 6, Wis 10, Cha 8]: A mana hound has a base AC of 14, is a Medium creature, and has a walking speed of 50'. In addition, it can teleport up to 15' as part of its movement each turn, deducting from its total movement normally. As an action, it can deliver a bite infused with unstable arcane power as a dex-based melee weapon attack. On a hit, the target takes 1d8+Dex piercing damage. If the target is maintaining concentration on a spell, they are considered to have vulnerability to this damage. By expending its Fel Might, the mana hound can instead deal Xd8+Dex necrotic damage with attack and force its target to suffer disadvantage on any concentration saving throw made due to this damage, where X is the number of damage dice used by cantrips at your level.

Brimstone Summons
As a faustian masters their art, ever mightier fiends are ready to heed their summons. Beginning at 13th level, you can sacrifice a spell slot or use of your Mystic Arcanum in order to summon a fiend with a CR no greater than the level of the arcanum slot you sacrificed, or no greater than 4 if you sacrificed a spell slot. The fiend is loyal to you and follows your commands to the best of its ability for one minute, at which point it is dismissed. Maintaining this effect requires concentration. Losing concentration will result in the fiend being dismissed early. In addition, you can summon the following fiends with your Dark Pact feature.
 * Succubus [Str 8, Dex 14, Con 10, Int 14, Wis 10, Cha 16]: A succubus has a base AC of 14, is a Medium creature, and has a walking speed of 30' and a flying speed of 30'. As an action, she can deliver a befuddling touch as a cha-based melee spell attack. On a hit, the target takes 1d4+Cha psychic damage, and is Charmed by the succubus until the end of her next turn. By expending her Fel Might, the succubus can instead deal Xd4+Cha psychic damage with attack and cause its target to be charmed by an ally within 30' in addition to the succubus herself, where X is the number of damage dice used by cantrips at your level.
 * Felguard [Str 16, Dex 14, Con 14, Int 8, Wis 12, Cha 8]: A felguard has a base AC of 15, is a Medium creature, and has a walking speed of 30'. As an action, it can cleave through foes with its demonic axe as a str-based melee weapon attack. On a hit, the target takes 1d12+Str slashing damage. By expending its fel might, the felguard can instead target up to three separate creatures with this attack and can instead deal Xd12+Str slashing damage on each hit, where X is the number of damage dice used by cantrips at your level.

Army of Darkness
The fiends at your beck and call are legion. Your enemies will drown in a tide of hellfire. Beginning at 18th level, you can summon multiple fiends with your Dark Pact feature. A single bonus action empowers only one of your fiends with Fel Might, but you may empower all of them at once by taking an Action. Each creature beyond the first consumes a spell slot, preventing that slot from being used while the fiend is summoned. Even if one of these excess summons is dismissed or destroyed, the locked slot remains unusable until you take a short or long rest.