Mirror Walker

As an archetypal Mirror Walker, you have gained access to a mysterious and little-known level of reality that some call the Mirror Realm: not so much a separate world from the Material Plane, or even a single, cohesive plane of existence by itself, but a bizarre patchwork of semi-realities, each a reflection of an object or location in the Material Plane.

The very natures of Mirror Walker rogues are fundamentally altered, allowing them to use mirrors and other reflective surfaces to interact with and even briefly enter into the Mirror Realm. These unique abilities help them to excel at such tasks as spywork, thievery, laying ambushes, escaping pursuit, and scaring the living daylights out of unsuspecting folk.

Mirror Walk

When you choose this archetype at 3rd level, you gain the ability to use mirrors and other reflective surfaces as openings into the Mirror Realm. At any time on your turn, you can spend half of your base movement speed to enter into this realm through a mirrorlike surface within 5 feet of you that is large enough for you to fit through. This counts as moving into the reflection’s space for the purpose of provoking opportunity attacks against you.

While you remain in the Mirror Realm, the following effects apply:

• You occupy the same space as the surface and have total cover from all attacks originating outside it.
• You appear as a reflection in the surface and can see out of its surface as if it were a window, but no other physical or sensory effects besides light can pass through the surface.
• Creatures outside that can see you can target you with spells and other effects that can target a single creature, and you can likewise target creatures that you can see, but effects that deal damage other than psychic, or apply the deafened, grappled, poisoned, prone, or restrained conditions, fail to do so.
• You can spend half of your base movement speed to exit the Mirror Realm, emerging in the space in front of that surface. You then have advantage on the next attack roll you make before the end of your turn.

Mirror Step

At 9th level, you have learned how to move from one reflection of the Mirror Realm to another. While you are in the Mirror Realm, you can spend half of your base movement speed to occupy another reflective surface within 60 feet of you. The surface you move to can be of any size, but you cannot exit through it unless it is large enough for you to fit through.

Refractive Strike

Also at 9th level, you are able to briefly slip some of your attacks through the Mirror Realm, allowing you to bypass your enemies’ defenses. Once per turn when you make a weapon attack, you can choose to gain a +5 bonus to the attack roll. You can make this choice before or after you see the roll, but before the DM says if the attack hits or misses. If the attack hits, it counts as a critical hit.

You can use this feature a number of times equal to your proficiency bonus, and you regain expended uses when you finish a short or long rest.

Create Reflection

Starting at 13th level, you learn how to summon your own openings into the Mirror Realm. As a bonus action on your turn, you can cause one surface of Large or smaller size within 60 feet of you that you can see to become a portal into the Mirror Realm for the next minute, or until you use this feature again. The surface appears to become mirrorlike for the duration, allowing you to use it as a reflective surface for your Mirror Step feature.

While the portal is open, you can freely move objects into and out of it, provided those objects can fit through it. In addition, if you enter one of these portals using your Mirror Step feature, you can take one creature along with you that you can touch. If the creature is unwilling, you must have it grappled as you enter.

Creatures occupying the same reflective surface can act normally towards each other, including targeting each other with attacks and damaging effects, and can interact with any objects there as normal. Any creature other than you follows all the rules outlined in your Mirror Step feature, except that it cannot move to other surfaces or exit the Mirror Realm by itself. 

Whenever you move between or exit surfaces, you can choose to take any creatures or objects that are in the same surface along with you. Alternatively, you can choose to move or exit without the creatures or objects, trapping them in the Mirror Realm. A trapped creature can attempt a DC 15 Charisma saving throw on each of its turns, exiting the Mirror Realm on a success.

Trick of the Light

Starting at 17th level, you have become so attuned to the Mirror Realm that you can vanish into it to avoid harm. Whenever you take damage from an attack or fail a saving throw against a damaging effect that you can see, you can use your reaction to take no damage from the attack or succeed on the saving throw. You then appear to shatter into mirrorlike fragments, materializing in the nearest reflective surface.

Once you use this feature, you can’t use it again until you finish a long rest.