Soul-Eater Bloodline
The Soul-Eaters are not so much a bloodline of direct decedents, than a bloodline of random magic caused by strong necrotic energies.
These energies form a vacuum of a vessel, which absorbs the souls of all those who die around them. This necrotic energy, while gifting the vessel magical energies, also ends up creating a creature slightly less than mortal.
At first the vessel may appear slightly pasty and sickly; however, as they grow in power and absorb the souls of those who die around them, the necrotic energy begins rotting their body. Those that make it to their full potential often look as rotten as a thousand years old lich, and have lost all sense of their own personal identity.
Vessel of the Dead
You absorb the souls who die around you, slowly becoming less and less attached to your own soul.
Starting at level 1, any creature who dies within 30 feet of you, or is killed by your magic, and who has a soul, has that soul absorbed into them. Once like this that creature can not be resurrected, unless you wish to let go of the soul, short of a wish spell. There is no limit to the number of souls you may hold, but you may choose whether or not you hold a soul at any time.
You voice becomes that of the legion once you do realize your bloodline. Each word sounding as thought it were said by every single soul within you at once. Additionally, any attempts to see you through true sight reveal what looks like every soul within you placed one on top of the other.
You may choose to use the voice of any soul you possess, though usually it is your original soul's, instead of holding the voice of the legion.
Over the course of a short or long rest, you may converse with the souls within you speaking through them and attempting to look for information. At the end of the long rest, you may make an intelligence check with advantage. At the DM's discretion, it may be decided a specific soul within you may be both posessing knowledge you want and willing to part with it.
Keeping track of souls
While you do absorb the souls of all those who die near you, and who you kill with your magic, it is in no way important to keep track of how many souls or who souls are in you. However, since you are able to use the voices of others, interrogate for information, and stop from resurrecting, you may wish to just keep a small list of important names.
For example, the bandit you killed probably isn't important enough to list, but but a cultist or especially mob leader might be something you'd wish to list.
Telepathy
As you are able to communicate with the souls within you, you are able to communicate with the souls of others.
Starting at level one, you have telepathy for 60 feet.
Powerful mind
The souls within you have begun melding into a singular mind and purpose, which stands against any attempts to manipulate it.
At 6th level you may add your charisma modifier to wisdom saving throws.
Additionally, due to the thousands of souls stirring in your head at once, any one who attempts to forcibly read your mind must make a wisdom saving throw, or take a number of psychic damage equal to your level times your Charisma modifier (minimum 1), or half as much on a successful saving throw.
Soul Flying
You've learned to swirl the souls within you in order to create a simple flying effect.
At 14th level you gain a fly (hover) speed of 25 feet. You may not use this while wearing medium or light armor.
Souls of the living
You've learned to grasp the souls of the living, and turn them to your will.
Beginning at 18th level, you may spend 5 sorcery points to attempt and control the soul of a creature you can see, within 30 feet of you. That creature must succeed on a wisdom saving throw, or else become under your control for one minute.
While it is under your control you may control its turns, though you can not make it talk, cast spells, or make it fail mental saving throws.
The creature may repeat the saving throws once a round, when taking damage.
