Fading Soul

Your magic feels more like a curse, you (and your equipment) disappear from existence and reappear at seemingly random points, and you are always aware that at some point, you may be unable to reappear. How and why this happens is up to your imagination, perhaps a powerful force does not want you to exist, perhaps you are a powerful force that does not want yourself to exist but you can not get yourself to stay gone, or perhaps you just disappear occasionally and don't know why. The situations in which you disappear are often not during combat (because it is seemingly random and most fights don't even last for an in-game minute) but it can occur. The time between a disappearance and a reappearance can range from a few minutes to a few days. The timing of these disappearances are either decided by the player or the DM, to make the most out of the potential, it is often interesting to have the character disappear at a fitting or inconvenient time. There is, however, a small amount of control that you do manage to have over it, which occurs as many of the abilities granted by this subclass. What you experience in the time between disappearing and reappearing is decided by the player or the DM, some examples include, just complete darkness, a location within your imagination (either always the same or occasionally changing), an outside view of everything that happens near the return point, or the Ethereal Plane. Unless you are using a normal plane of existence, you do not require food or water while disappeared, you can attempt to take a short or long rest, but since your reappearance is randomly timed, it might be cut short. (This subclass has a lot of abilities, however, many of them are situational)

Return point

Whenever you disappear, there is always a defined point that you reappear close to, this can be chosen as an action. The return point is always an object or person and you reappear anywhere you chose within 10 feet of that point. You can choose a new point as an action, the selected point must be in sight when decided, if you select yourself (or something that would disappear with you), the point is the place that you were in before you disappeared. It is not likely that you would have never used this ability (especially if you were a fading soul in your backstory), but if you somehow haven't, the default location is either you or your arcane focus if you have one and it makes sense with how you became a fading soul.

Sudden Vanish

By holding on to just a little bit of control over your spontaneous disappearances you can disappear for a turn as an action or a reaction to something being done to you. You can not do anything until you reappear, if you used this ability as a reaction to being attacked, you reappear upon the end of the attacker's next turn (or at least after when that turn would happen assuming the creature is alive), if this was done as an action, you reappear at the start of your next turn. At level 1 this can be done twice before taking a short or long rest, and the amount of times you can use this increases to 3 upon reaching level 4. 

Choice Vanish

While you still disappear randomly, you have found a way to cause a disappearance to happen, (for role play purposes, you may want to wait for a fitting point in the story for your character to start using this ability) this can be done as a bonus action, but you do not have any control over when you reappear.

Co-Vanish

At level 2 (it is technically level 1, but it requires sorcery points, which makes it 2), you can now take a creature with you when you vanish. When using the choice vanish ability, you can choose to spend 2 sorcery points to try to take a creature with you. This requires you to be touching the creature and the creature (if it has at lest 6 intelligence) will realize what you are doing right before it happens. If the creature resists, you fail, but when you reach level 6, you can try to force an unwilling creature. It must make a dexterity saving throw (as if this were a spell), on a success, nothing happens to the creature, upon a fail, the creature is taken with you. When pulled into the disappearance, the creature will be standing near you, seeing the same surroundings, and capable of anything that it could do on normal, unfamiliar terrain. The creature will reappear at the same time and in the same way that you do, but if it kills you, then it will be unable to reappear unless it can travel to another plane on it's own, you also know this fact and can use it to encourage the creature not to attack you. Most creatures will not completely understand what is happening when you do this, and, as a result, may be more likely to listen to any explanation you give of it or believe a lie that you tell about it (the implications of this sentence are up to the DM). Regardless of how long you are vanished, a co-vanished creature will not stay vanished for longer then 3 days (unless it kills you). At level 6, you also gain the ability to co-vanish with multiple creatures, but you need to spend an additional 2 sorcery points for every creature after the first one. At level 14, you can use co-vanish on any creature within 10 feet of you or your return point, and at level 18 this can even be done while already disappeared.  

Enhanced Sudden Vanish

Upon reaching level 6, you can now use your sudden vanish ability with much more skill you can spend 2 sorcery points to gain an additional usage of sudden vanish, you can use this ability as a bonus action, and when using this as a reaction, you appear at the start of your next turn. You also gain the ability to spend a sorcery point to use this ability on a willing creature you are touching.

Refusal

Upon reaching level 14, you gain a little more control over your disappearances, you can now spend 3 sorcery points to cancel a disappearance. This can even work on choice vanishes, although you would probably only want to do that if the target of a co-vanish succeeds the saving throw.

Relocate

As a bonus action you can spend 3 sorcery points to do what is effectively a sudden vanish that only lasts for the time of the bonus action. Due to the way that reappearing works, you effectively teleport 10 feet in any given direction.

Strong Control

Upon reaching level 18, you have acquired so much control over you disappearances that you often go for weeks to even months without disappearing unintentionally and it is no longer possible for you to disappear indefinitely unless you will it yourself. You can now choose any point after 3 minutes to reappear after disappearing.