Aurora's Anonymous Accomplice

You carefully inscribe intricate runes onto a mirror for the entire casting time of the spell, finishing the ritual by uttering a command word. After the ritual is complete your reflection becomes untethered from your world, now existing as an independent entity. The reflection is a creature, it can take actions and otherwise be affected as a normal creature. It appears to be an exact copy of the caster, using all the statistics of the caster.

Your reflection is friendly to you and creatures you designate. It obeys your spoken commands, moving and acting in accordance with your wishes and acting on your turn in combat. The reflection lacks the ability to learn or become more powerful, so it never increases its level or other abilities, nor can it cast spells. As an inhabitant of the Mirror Plane, the reflection can only be perceived by creatures on the Material Plane who peer into mirrors that have a line of sight to the reflection. Creatures with Truesight can see a faint shimmering projection of the reflection where it would normally be located in the Material Plane.

The reflection cannot interact with creatures nor objects that are worn by creatures. It can however interact with other objects, which upon being worn or carried become a part of the reflection, and subsequently become invisible on the Material Plane. The reflection can still take damage from attacks, spells, and other effects on the Material Plane. If the reflection drops to 0 hit points, the spell ends and the caster takes 5d10 force damage as your reflection becomes retethered to yourself. If you recast this spell while it is currently active the reflection reappears at the mirror you casted with full HP and the statistics of the caster at the time of recasting. If the command word is uttered within 5 ft of a mirror, and a spell slot of 3rd or higher is expended, the caster can have a short message of 25 words or less be transmitted telepathically to the reflection, regardless of distance in the Mirror Plane. The reflection can reply back with a message of 25 words or less.