- You have advantage on saving throws against being poisoned, and you have resistance to poison damage. 

- You are immune to disease. 

- You don't need to eat, drink, or breathe. 

- When you take a long rest, you must spend at least six hours in an inactive, motionless state, rather than sleeping. In this state, you appear inert, but it doesn't render you unconscious, and you can see and hear as normal. 

For a number of times equal to your Intelligence modifier, you are able to cast the See Through spell. The duration of this spell is limited to 10 minutes. All expended uses of this feature are recharged after a long rest. 

Once per long rest, as an action, you can release an amorphous body of shadow and/or light that is your true form manifested in the material plane. This true form temporarily leaves behind whatever body you were possessing and can act independently of it; however, you can only do so for up to an hour and must remain within a number of miles equal to your Intelligence modifier. Your statistics are replaced with those of the "Shadow" monster from the Monster Manuel; however, you retain your alignment and proficiencies. Similar to Wild Shape, the health points of this true form are separate from your character's health points. If at any point your true form is reduced to 0 health points, your essence immediately retreats back to your body and any leftover damage from the attack is taken by your body. Furthermore, if your body is attacked while you are in your true form, it is considered unconscious and would continue taking damage. If your body is reduced to 0, then your true form immediately ends and returns to your unconscious body. In the event that you immediately die, your true form still disappears. 

At certain character levels, your true form improves: At 3rd level, you are no longer vulnerable to radiant damage and you gain advantage on stealth and sleight of hand checks while in dim light or darkness. At 5th level, you gain a flying speed of 20 feet. 

Death to your character is but a temporary inconvenience. Unless there is a specific effect that would negate this as designated by your DM, if your character dies, you can manifest back into the material world. Roll a 1d4 to determine the number of days it will take for you to return. Once that time has passed, you must choose a new form to infuse your essence to, but you are unable to do so with your previous body, regardless of its condition when you died. Discuss with your DM where/how you manifest.

Additionally, the journey away and back to the material plane is not a pleasant one, and your essence and mind warp. You lose one skill, armor, weapon, tool, or language proficiency. Additionally, your maximum HP is reduced by a number of points equal to your character level.