Shadow Touched - Fullfeat

Your exposure to the Shadowfell’s magic has changed you, granting you the following benefits:

• You learn the invisibility spell and one 1st-level spell of your choice. The 1st-level spell must be from the illusion or necromancy school of magic. You can cast each of these spells without expending a spell slot. Once you cast either of these spells in this way, you can’t cast that spell in this way again until you finish a long rest. You can also cast these spells using spell slots you have of the appropriate level. The spells’ spellcasting ability is Wisdom if you do not already have a spellcasting ability; otherwise the spell uses your existing spellcasting ability (if you have multiple spellcasting abilities, choose one at the time of taking this feat). 
• When you take the hide or disengage action while you are in dim light or darkness, you gain a single shadowy illusory duplicate of yourself. As long as you remain in dim light or darkness the shadowy duplicate moves with you and mimics your actions exactly until it is destroyed, shifting position so it's impossible to track which image is real. You may only have one such duplicate active at any given time. 
  • Each time a creature targets you with an attack while the shadowy duplicate is present, roll a d20 to determine whether the attack instead targets your duplicate. You must roll an 11 or higher to change the attack's target to the duplicate. 
  • The duplicate's AC equals 10 + your Dexterity modifier. The duplicate is destroyed if and only if: an attack hits the duplicate; if you start or end your turn outside of dim light or darkness; or if you are under the effect of the mirror image spell. The duplicate ignores all other damage and effects, and can withstand brief exposure to bright light. 
  • A creature is unaffected by this ability if it can't see, if it relies on senses other than sight, such as blindsight, or if it can perceive illusions as false, as with truesight. 

[Part of a project to upgrade Half-feats (those granting lesser abilities/effects alongside a single point of ability score increase) to Fullfeats (foregoing any ability score increase to receive a more fully-balanced ability/effect).]