Shadow Characters are essentially sapient shadows, people from the shadow (from the Grey) that have developed an awareness and sometimes find themselves in the Actuality. They have no souls, no qualia, no magic. Of course we can tweak this to fit what you want but this is essentially the mechanics to have a Shadow Character:
Start with 6 levels of skills and divide it in any way but no more than 2 levels per skill.
They have no heart, order, forte, soul, or foundation and do not start with a character arc (but can get a character arc in the normal way by spending Acumen earned).
They can possess 2 ephemera objects at one time.
Suffer damage as a regular character. They have the 4 rest but since they don’t have any pools, they use the one-action rest to heal 1 Injury and the ten-minute or one-hour rest to heal 1 wound or 1 anguish.
If they die, they don’t go into the Pale, they are gone forever.
They don’t earn joy or despair, just Acumen.
The can spend Acumen on the following:
Skills as normal
Hardiness (4 Acumen): +1 Injury before their injuries convert to Wounds.
Gathering One’s Wits (4 Acumen): Can use their one-action rest to assess the current situation and get a +1 bonus to all actions for the rest of the encounter. Select this ability only once.
Magical Enhancement (6 Acumen): Can add one magic die to an action one time. Refreshes each time they use a ten-minute or one-hour rest.