Nine-Tailed Inheritor

Through your veins flows an ancient and mystical energy, belonging to a powerful, demigod like being. The great trickster, master of deceit and manipulation. It has charmed angels and devils alike, even some gods have fallen for it's tricks. Wherever your parent was their passing fancy or your bloodline traces back to a powerful Kitsune, you are one way or another related to this being. It's power a joyous flame in your heart, pushing you to adventure, to trick and prank, to never feel boredom. But you must be weary, lest this flame consumes you.

Creators Note - For the purpose of implementing this origin and the far eastern mythos, yokai and the like could be considered as Fey (being natural creatures of the spirit world). This particular origin refers to an evil variant of the Kitsune (Yako). For the good variant (Inari) considering giving the Magic Tail feature to the Divine Soul origin. GM's should also consider allowing sorcerer's of this origin to take illusion and enchantment spells from outside the sorcerer spell list as its lacking much of the flavourful options such as Mislead and Hallucionary Terrain. 

Magic Tail

At 1st level, when you chose this origin, you grow a fox tail and a pair of fox-like ears. As you gain levels you grow additional tails to contain the volatile power suffusing you. The amount of tails you have are equal to the maximum level of spell you can cast, up to 9. You may suppress these features as an action and they remain suppressed as long as you concentrate on this ability as if you would concentrate on a spell.

You know Minor Illusion and Produce Flames cantrips, these count against your maximum known cantrips.

Fox Fire

Beginning at 1st level, whenever you cast an illusion or enchantment you may siphon some of the residual magic to conjure a small dancing flame next to you. You create an amount of dancing flames equal to the level of spell cast and you can never hold more flames than your tails at once. These flames last for 10 minutes and can be manipulated like Dancing Lights.

You may use your bonus action to hurl one of the flames at a creature within 30ft of you as a spell attack, if you hit they take 1d4 + your charisma modifier fire damage. You may also choose to expend multiple fox fires at once combining them, increasing the damage die by 1 step each time up to a maximum of 1d12 (1d4 becomes 1d6, 1d6 becomes 1d8 etc).

Trickster’s Arcana

At 6th level your very words become subtly suffused with your ancestor’s beguiling power, you gain proficiency in your choice of either deception or persuasion, if you have both already gain expertise in one of them instead.

Whenever you succeed a persuasion or deception check against one or more creatures you may have them become vulnerable to your magic. They have disadvantage on their saving throws against your next illusion or enchantment spell. This effect lasts for 1 hour or until it is discharged and you cannot affect the same creature again until you complete a long rest. Creatures immune to charms are immune to this.

Fox’s Guise

At 14th level, you gain the ability to use Alter Self at will but only to turn into another humanoid of small or medium size.

You may also use your action and spend 3 sorcery points to shapeshift into any beast of CR 1/2 or lower you have seen before. You retain your mental statistics and personality and you gain the physical characteristics and abilities of the chosen creature, you can remain in this form for up to 4 hours and can end it early as an action. If your new form is brought to 0 hp any excess damage is carried over to you and this ends early. You cannot speak or cast spells while shapeshifted this way.

Aspect of Mischief

Beginning at 18th level, whenever you cast an illusion or enchantment spell while already concentrating on another spell or effect you may spend 4 sorcery points to not lose concentration, allowing you to concentrate on both effects simultaniously. You can only concentrate on 2 spells or effects in this manner at a time and should you lose your concentration, you lose both. If both spells or effects allow you to modify them (such as with Major Image), you can modify both simultaniously as long as they require the same action.

You are also immune to any spell or effect which discerns truth about you, such as a zone of truth spell, a Planetar's Divine Awareness and truesigh.