Out of a mixture of boredom, disliking Divine Soul, and wanting to invent a subclass for fun, I decided to make a new Sorcerer subclass. Figured I’d post it here to get some feedback and whatnot, so here goes.

Godly Ancestry

You draw your powers from a god in your lineage, granting you divine powers similar to a Cleric. You don't have to worship any god to gain these powers, unlike a Cleric. If the god is good-aligned, you gain many healing and buffing abilities, along with a heavenly theme. If the god is evil-aligned, you gain damaging and debuffing abilities, along with a hellish theme. If the god is neutral-aligned, you gain a mixture of both.

Deific Ancestry:

When you choose this origin at level one, you must choose between being related to a good-aligned, neutral-aligned, or evil-aligned god. This determines what abilities you gain as you level up, and provides a few abilities at level 1.

Good: You can speak, read, and write Celestial. You gain the Cure Wounds and Guidance spells.

Evil: You can speak, read, and write Infernal. You gain the Inflict Wounds and Thaumaturgy spells.

Neutral: You can speak, read, and write either Celestial or Infernal, your choice. You gain the Command and Mage Hand spells.

Spells gained by this trait count as a Sorcerer spell for you but do not count against your total Sorcerer spells.

Heavenly Resistance:

Starting at level 1, you gain resistance to both radiant and necrotic damage. If you gain resistance from another source, this becomes immunity instead. 

Good: You heal the amount reduced by radiant damage. This turns resistance into functional immunity.

Evil: You heal the amount reduced by necrotic damage. This turns resistance into functional immunity.

Neutral: You heal half of the damage reduced from both radiant and necrotic damage, rounded down. This turns resistance into a 75% reduction.

Glowing Aura:

By level 6, your abilities begin to manifest in a physical form that radiates off you. This glowing aura can be activated as an action, and lasts for 1 minute or until ended as a bonus action. The light of the aura shines for 10 feet of bright light and 30 feet of dim light beyond that. This effect can only be used once per long rest.

Good: Your aura is a heavenly white, radiating peace and providing inspiration to your allies. While active, all creatures you choose within the light of your aura may add 1d6 to one attack, ability check, or saving throw per turn.

Evil: Your aura is a demonic red, radiating pure evil and corrupting the minds of your enemies. While active, all creatures you choose within the light of your aura must make a Wisdom saving throw against your spell DC at the beginning of their turns. If they fail, they must attack the closest creature for their action that turn. Constructs, undead, and creatures immune to being charmed are immune to this effect.

Neutral: Your aura is a calm grey, radiating a mixture of peace and evil. While active, at the beginning of each of your turns you can choose up to three creatures within the light of your aura (not including yourself). These creatures heal 2d4 HP. Alternatively, you may choose to deal 2d4 psychic damage to the chosen creatures. You may not mix the two. Constructs aren’t affected by either effect, and undead instead take 2d4 radiant damage from the first effect.

Divine Strike:

Starting at level 14, you gain the ability to empower your spells with divine energy. When attacking with a spell, you may spend any number of sorcery points to deal an extra 1d6 damage for every point spent if it hits. The damage type is determined by your ancestry. Radiant for good, necrotic for evil, and psychic for neutral. If the spell misses, the sorcery points are wasted. The extra damage applies only if the spell itself deals damage to the target, and it is not reduced by succeeded saving throws, such as with Fireball.

For spells that hit multiple targets, the extra dice are split however you choose between them. For example, for a Fireball that hits three creatures, if you spend 3 sorcery points then you could add an extra 1d8 for each enemy, put all 3d8 on one, or any other combination. 

This ability cannot be used on Magic Missile.

Ascension:

Starting at level 18, your godly heritage allows you to ascend beyond mortal limits at the cost of most of your energy. As a bonus action on your turn, you may ascend, causing your eyes to glow with powerful white, red, or grey energy. 

This form grants you immunity to all damage, gives you advantage on all saves and checks, and causes you to deal an extra 2d10 radiant, necrotic, or psychic damage based on your heritage on all magical attacks that have an attack roll.

This form ends once it becomes your turn again. Once this form ends, you fall prone, your turn is skipped, and you become vulnerable to all damage types until the beginning of your next turn. This ability can only be used once per long rest.

Glowing Aura is too strong. The Evil aura in particular is vastly overpowered. Repeatedly being affected by a domination effect is crazy.

Any ability that you have to write "cannot be used with magic missile" is a bit of an issue. Divine Strike is too potent, and encourages the sorcerer to blow all their sorcery points on their first hit on an enemy creature.

Overall I think that this is essentially three different sub-classes, since you have to permanently choose one of them.

Immunity at level 1 is too strong. Id either change it to just resistance with no way of obtaining immunity OR if you want to keep the heal, turn it into a reaction instead so that it is not "always on" 

Yeah it's a no-brainer to combine this with aasimar for double immunity at level 1. This is way too strong. Immunity for PCs shouldn't happen until like 15+ if ever.

Magic missile neither requires making an attack roll or a saving throw, so you can attach a feature to those mechanics and not have to worry about MM shenanigans.

I would make Glowing Aura weaker but with more uses. All the level 1 stuff is passive and most subclasses are designed to provide several moments per adventuring day that allow you to showcase your subclass powers.