Survivor's Origin

Unlike most sorcerers, your birth was mundane with no arcane inheritance passed down from strange ancestors. Instead you gained your sorcerous powers after you managed to survive an experience that left you on the brink of death. Since that experience you've had a preternatural sense for danger and a ghostly companion that either can't or won't leave you alone. Some Survivors, as sorcerers who share your origin are called, develop cordial relationships with their phantom, while others find their spectral companion to be a relentless nuisance.

Survivors Spells

You learn additional spells when you reach certain levels in this class as listed below. Each of these spells count as a sorcerer's spell for you but doesn't count against the number of spells you know.
When you cast a spell from the Survivors Spell list, you can cast it normally or by expending a number of Sorcery Points equal to the spells level.
(List contains homebrew spells I've created)

1st.           Unseen Servant.
3rd.           See Invisibility
5th.           Speak with Dead.
7th.           Death Ward.
9th.           Small Death.

Ghost-like Companion

At 1st level, you learn the find familiar spell and can cast it as a ritual. The spell doesn't count against your number of spells known.
When you cast this spell, you can only choose the form of a specter, which becomes your Ghost-like Companion. Instead of a celestial, fey, or fiend this familiar's creature type is undead.
As an action, you can command your companion to turn invisible until it attacks or you cast a spell through it. While invisible, it leaves no physical evidence of its passage, so it can only be tracked by magic. Any equipment or objects it is holding remains visible.
Additionally, at 3rd level, when you take the attack action, you can forgo one of your attacks to allow your familiar to make its Life Drain attack with its reaction.

Sixth Sense

Starting at 1st level, when you make a Dexterity ability check to determine initiative, you gain a bonus to the roll equal to your Charisma modifier.

Prowess of Phantom

At 6th level, your bond to the specter summoned by your Ghost-like Companion feature empowers it further.
You gain the following benefits:
Your specter's maximum hit points increase by 4 times your level in this class.
Your specter can deliver spells of any range, not just touch. Apart from this change, it follows the normal rules of casting a spell through your familiar.
When you use your action to cast a spell, you can use a bonus action on the same turn to command your specter to use its Life Drain attack against a creature within range of your choice.

Deathly Sallow

Also at 6th level, you gain resistance to necrotic damage.
In addition, when you cast a sorcerer spell that deals damage, you can change the damage type dealt to necrotic.

Specter Possesion

At 14th level, as an action you can direct your companion specter to attempt to possess and enter a creature of your choice within 5 feet of your specter. When you do, the creature must succeed on a Charisma saving throw against your spell save DC or be possessed by your specter for 1 minute. During this time your specter cannot be affected by spells or abilities, take actions, or interact with in any way.
While the target is possessed, you have a telepathic link with it as long as the two of you are within 100 feet. You can use this telepathic link to issue commands (no action required), which it does its best to obey. If the creature completes the order and doesn't receive further direction from you, it defends and preserves itself to the best of its ability, taking the Dodge action if it has not used its action already.
Each time the target takes damage, it makes a new Charisma saving throw against the possession. If the creature succeeds, the possession ends and your specter companion reappears in the closest unoccupied space.
Once you use this feature, you can't do so again until you finish a short rest.

Death Becomes You

At 18th level, you can transmute your physical form into a spectral one when you near death. When you take damage that would reduce you to 0 hit points, you drop to 1 hit point instead and gain temporary hit points equal to half your hit point maximum. At the start of each of your turns, you lose 5 temporary hit points and all creatures of your choice within 30 feet of you take 5 necrotic damage. While you have temporary hit points granted from this feature, you have resistance to all damage, a fly speed of 30 feet, and can move through creatures and objects provided you end your movement in an unoccupied space.
Once you have used this feature, you can't do so again until you finish a long rest.