Flavor text.

Basic Abilities

• Extraplanar Being: As a being hailing from another dimension, the Material Plane is not your home. You occupy a physical body that is compatible with the Material Plane, and while you can imbue it with Void-based powers, it is ultimately a physical body that must obey the laws of Physics (more or less). If that body is permanently destroyed, you lose your anchor on the Material Plane, and your essence returns to the Void. Extraplanar beings cannot invite themselves into the Material Plane under normal circumstances--they typically must enter through means originating in the Material Plane itself (although godlike beings can manifest across the planar barrier without assistance). By default, you do not possess the ability to form a new physical avatar if yours is permanently destroyed
• Immortal: Unless killed on your home plane, you cannot permanently die. Killing your physical avatar on the Material Plane causes your essence to return to the Void. Your mind, memories, and powers remain intact, but you do have to create a new body if you ever return to the Material Plane.
• Physical Form: When you create your physical body, you may choose its form. By default, it is a medium humanoid form, whose particular appearance you choose. This does not change once created, unless you gain some other ability to modify your appearance.
• Restless: Your physical body obeys the laws of Physics, but it is not required to obey the limitations of biology. Even if you take the form of a human or other race that requires sleep, you do not need to sleep in order to function. You can do so if you wish.
• Shadowy Nature: Gain Resist 50% (shadow damage).
• Control Light: At will, as a swift action, you can change the ambient light levels within 20 squares. You can adjust light levels by one step in either direction on this scale: sunlight, indoor light, dimness, darkness.
• Alien Mind: Any attempt to read your mind, introduce a charm or compulsion, plant memories or inject sensory input, etc, causes harm to whoever is intruding. Attacker suffers heavy psychic damage, Int negates, but if they choose to roll defense, they cannot continue their attack. If they take damage, they must roll Concentration as normal.

Ancestry Powers

At level 3, 7, 11, 15, and 19, you can select an Ancestry Power from the list below.

• Voidspace: You have your own private demiplane in the Void. You can create a doorway into this space, which is large enough for a medium creature to fit through. While you remain in the space, the doorway must remain in the Material Plane, unmoving. You can make the doorway disappear when you are in the Material Plane, and can re-summon the doorway anywhere else (while within range). The space inside the void is essentially limitless. However, it does have all the attributes of the Shadow Realm, making it...unhealthy for normal living creatures. You like it just fine, natch.

Notes

Brainstorming more powers

• Dispersion: Encounter, swift; you become gaseous, gaining immunity to kinetic damage, and Resist 50% (thermal, explosive). You cannot take physical actions in this form, but you can move, albeit at a speed of Fly 2 instead of any normal speed you might have. You may remain in this form if you Concentrate; otherwise you revert to normal form.
• Visage of the Void: Encounter, std; you shift your appearance briefly to something resembling your "true" form, a visage so unimaginable that onlookers without the Alien Mind ability suffer merely from viewing it. You either affect a single target within range, causing heavy psychic damage plus frightened (Wis ends), or a cone 4, causing medium psychic damage plus shaken (Wis ends).

Ideas:

• Phantasm
• Phantasmal Killer
• Darkness (improved Control Light)
• Shadow Double (rank 2 or higher)
• Ethereal (Shadow) Jaunt: rank 3
• Reactive Dispersion
• Chill Touch