You need to perform a simple ritual. First, find a mirror big enough to show your whole body, head to toes. Then, look deep into the eyes of whatever creature is mimicking you, and then start to unleash as much wrath upon it as you can. Scream at it, insult it, do everything to irritate it. Think about the worst moments of your life, and use your anger and despair to attack this creature. If you have done everything right, your reflection should go away. This is your chance to enter the Mirror Realm, as nothing is blocking your path anymore. Now you might wonder: “Why should I do this?”. The Mirror Realm is designed to perfectly mimic our world. You can do whatever you want — steal, kill, break. The creatures that live in this world don’t have feelings, nor can they experience pain. There are no consequences for your actions.
But there is one catch. The beings inhabiting this realm really don’t like visitors. Soon they will try to scare you away. You might experience horrifying hallucinations or a feeling of incredible dread and despair. The longer you stay in the Mirror Realm — the more time they have to break you. You have about 24 hours before they begin to haunt you. If you want to escape, you need to enter the mirror you started your journey with. And if you somehow break it, then you are trapped. The Mirror Realm will show its true form and slowly devour your soul, leaving only an empty vessel. As you might see, the risks are high. But if you either want to do something unspeakable, either get a dose of adrenaline, this ritual is for you.
Good luck on the other side!