Animate Shadow

You pull wisps made from souls from those who succumbed to the Shadowfell's madness to give life for a living creature's shaddow. An unwilling target must succeed on a Charisma saving throw to resist losing his soul. The target succeeds automatically if it's under the spell Protection from Evil and Good. On a failed save, the target has his soul temporary split and a shadow creature is born. The shadow now has half of the remaining target's HP, and have access to class and racial features from it's counterpart. In case the target is a spell caster creature the shadow has half of the remaining spell slots from the target, rounded up and it can't cast spells that requires concentration neither does the target. If the target perishes so does the shadow, if the shadow perishes the target is no longer under the spell and it's shadow is back. The shadow is under your control until dispeled or until your concentration breaks. If the concentration is lost the shadow is now under the target's absolute control.

In dim light the shadow has advantage on steath checks and in darkness it becomes completely invisible. If the concentration is maintained until the spell ends the effect becomes permanent. If it does so, you no longer control the shadow creature, that becomes a weakened copy from the target(having the same traits that it had while a shadow). It might remain friendly to you, depending on how you have treated it. The shadow  basically tends to be a chaotic neutral counterpart of the target. The target can only regain it's shadow  is through the spell Remove Curse which must be used on the shadow killing it forever.