Wizard Subclass - Demon-Summoner 'Goetia' Tradition [5e]

I've always felt that the niche of demonic summoner has long been denied to Player Characters. Whilst PCs can gleefully littler the battlefield with Fey, Undead, Elementals and 36 Dire Weasels, the much more august and storied tradition of summoning and binding Fiends is curiously absent. Xanathar's Guide tried to correct this by adding a slew of demonic summoning spells but almost all of them were hamstrung out of the gate (expensive material components or the summon creatures straight up ignoring you) as being strictly worse that conjuring an elemental or animal. Inspired by the Lesser Key of Solomon and the Ars Geotia, behold its fell majesty:

Goetia Tradition

Student of the Ars Geotica
Your extensive studies have made you highly adept at dealing with extraplanar creatures. Starting at second level, you may use your Intelligence modifier rather than your Charisma modifier when attempting to use Persuasion, Intimidation or Deception on beings with the Fiend, Celestial or Elemental subtype.

Knowledge of the Seals
You are adept at knowing the True Names of Celestials, Fiends and Elementals. Starting at second level, when summoning a variety of Fiend, Celestial or Elemental you have successfully summoned before, you know the True Name already. With a Fiend, Celestial or Elemental you have not previously summoned, you may make a Religion, History or Arcana check to determine whether you know the True Name of the creature - the DC is three times the creatures’ challenge rating.

Binder of Fiends
At sixth level, you add the Summon Lesser Demons spell to your spellbook if it was not there already. When casting the spell, you may choose from the options listed rather than roll a d6, and may choose which creatures appear.

Additionally, each summoned demon will have extra hit points equal to your Wizard level, and adds your proficiency bonus to attack rolls.

Infernal Contract

At tenth level, you add the Infernal Calling spell to your spellbook if it was not there already. You may ignore the component requirement for this spell once per long rest.

 

Penumbra of Royalty
Starting at 14th level, you can use magic to bring either Fiends, Celestials or Elementals under your control, even those summoned by other wizards. Choose either Fiends, Celestials or Elementals - this choice is permanent and cannot be changed. As an action, you can choose one creature of that type that you can see within 60 feet of you. That creature must make a Charisma saving throw against your wizard spell save DC. If it succeeds, you can’t use this feature on it again. If it fails, it becomes friendly to you and obeys your commands until you use this feature again.

Intelligent creatures are harder to control in this way. If the target has an Intelligence of 8 or higher, it has advantage on the saving throw. If it fails the saving throw and has an Intelligence of 12 or higher, it can repeat the saving throw at the end of every hour until it succeeds and breaks free.