Pact of the mirror
At third level your otherworldy patron bestows a gift upon you for yoir loyal service. The following is an option meant to add to those in the Player's Handbook.
Your Patron gives you a small shard of an ancient mirror that reflects a dark version of the world. While the shard is on your person, you know the mirror image spell and can cast it once without using a spell slot. You regain the ability to do so after a long rest. It doesn't count against your number of spells known.
In addition whenever you cast an illusion or conjuration spell you can ignore the verbal components of the spell.
If you lose your shard, you can perform a 1-hour ritual to receive a replacement. This ceremony can be performed during a short or long rest, and it destroys the previous shard. The shard shatters into glass dust when you die.
Eldritch Invocations
Glass Adherents
Prerequisite: Pact of the Mirror Feature
You can cast unseen servant at will without expending a spell slot or material components. When cast in this way you can only have up to two servants at any given time and when looked at through a reflective surface they can be seen as humanoid shadowy figures.
Argent Step
Prerequisite: 5th level, Pact of the Mirror Feature
When stepping into or out of a mirror you may choose to remain within the mirror for up to a minute. While inside the mirror in this way you may look out through the mirror to see its surrounding. Any creature that looks at the mirror sees you on the other side. If the reflective surface is broken or disturbed you appear in the closest available space and take 4d6 force damage.
With the exception of your shard; your origin and destination surface must be large enough for you to fit through.
Shroud of the Deceiver
Prerequisite: 9th level, Pact of the Mirror Feature
You learn the mislead spell and can cast it once without using a spell slot. You regain the ability to do so after a long rest. It doesn't count against your number of spells known.
Shattered Prison
Prerequisite: 12th level, Pact of the Mirror Feature
You can attempt to imprison a creature within your shard. As an action you can choose a restrained or incapacitated creature within 30 feet of you that must succeed on a Charisma saving throw against your spell save DC or be trapped, along with anything it is wearing or carrying in an extradimensional space inside your pact shard. If it succeeds, it is immune to this ability for 24 hours.
Creatures trapped in the shard don't age, and they don't need to eat, drink, or sleep. In addition the creature can't be harmed, although they perceive pain normally. A creature trapped within the shard can escape using magic that permits planar travel. Otherwise, the creature is confined to the shard until freed. The creature can bee seen when looking through the shard. You and the creature can communicate normally if you so choose.
You control every physical aspect of the extradimensional space and can populate it with illusory beings that look and act however you want. A creature trapped within the shard realizes the world around them is an illusion with a DC 20 investigation check.
You can only imprison one creature at a time and you may release them as an action.
