Shadowcaster

Walk Unseen
Beginning at 8th level, whenever you cast a spell that consumes a spell slot, you can use your bonus action before the end of the current turn to take the Hide action. You can make this hide check even if you are unobscured or have no concealment, simply melting away into shadows in plain sight. You become visible again at the end of your next turn if you do not find a tangible hiding location or activate this ability again. Additionally, learn the spell Invisibility, which does not count against your usual limit of spells known, and you gain proficiency in Stealth.

Shadowcast
Beginning at 13th level, you can weave magics from nothing but shadows and the darkness of your targets' minds. When you cast a spell of 5th level or lower, you can choose to shadowcast that spell instead. A shadowcast spell does not consume a spell slot, but any creature affected by it must (even if the spell is harmless) make an intelligence saving throw (against your usual spell save DC) before any of the spell's effects occur. If this saving throw is a success, that creature is unaffected by the spell. You may shadowcast a number of times between short rests equal to your Charisma modifier.

Umbral Empowerment
Beginning at 18th level, you can expend two uses of your shadowcast ability in order to shadowcast a mystic arcanum of 6th, 7th, or 8th level. Additionally, whenever a creature is unable to see you, it suffers Disadvantage on intelligence checks to disbelieve shadowcast spells.