It came out of nowhere.
Felix was flying through the shattered skies, enjoying the sights of the many portals, taking the occasional selfie. Then the threads of energy formed between the portals. Felix almost flew straight into one. That kind of thing never happened. And the threads multiplied and filled the air until one...
...Felix now is somewhere else entirely no idea how he got here. While flying through the wilderness the pain starts and eventually culminates with a blood-covered pebble coming out of his mouth. Which was only supposed to happen if Felix was somewhere else so far that the magic that allows his immortality couldn't reach and the only possible place like this would be another universe entirely.
An hour, he gives himself that much time and uses it, but by then Felix decides that crying isn't useful anymore no matter how much he wants to.
Instead Felix searches for civilization, since he is going to stay in this world for the foreseeable future.
It's like a bizarre blend between a church, a house, a castle, and an office building. Not really matching any of them, with features that try to clash with one another but still manage to produce a coherent and attractive, if odd, whole.
"Could be weirder" Felix says to himself.
Any obvious entrances? Signs of activity?
There's a big balcony on one side with huge glass overlook, might be a door. It looks like some kind of art gallery with lots of mirrors, maybe. There's also a very solid-looking barred door with a path leading down to the forest. There are scorch marks on and in front of it.
Well, he will enter through the balcony door. He will break it if necessary.
It opens fine.
It does look like some kind of art gallery in here. Various objects are strewn around. A flintlock gun, a blanket, a flute, a pantry full of mostly paper-wrapped foods, a wooden cart. A corner of the place is set up like a workshop with 'tools' that don't entirely make sense. The mirrors (and there are lots of mirrors) all reflect a version of things that's distorted in some way. This one reflects things as though they're made of tinted glass, that one makes everything white, this one covers everything in spikes...
There's a big spiral staircase leading down, if he wants to work through the near-maze of reflections and glass.
...Felix will not touch the suspiciously magical mirrors of potential doom. And touching the various objects should be avoided. Can he fly over the near-maze? Or mark the floor by scorching it with controlled fire?
He can mark the floor just fine. There are more mirrors on the ceiling, and there might be a clear path, but the light's playing tricks here and it's hard to be sure.
The sound of breaking glass comes from below, and a growl of frustration.
Urgh. Felix thinks. Call out and attract attention? Gren can't die in the dream, but not waking up could kill her...
Felix swallows and yells "Gren!?"
"What now?! Nightmare can't kill me with animal-Neuroi so, what, it's trying psychological warfare?"
"What? No. I'm here to rescue you. We need to talk you through a portal or you won't wake up."
"Yeah, sure, I believe you." She doesn't. More breaking glass. "I don't even know you."
"Felix Dalkaila," he says flinching at the breaking glass. "Why are you doing that?"
"Okay..." Felix says slowly since she is being cryptic. "anyway, all of this happening because an magical crystal touched you while you are asleep and while this place is real, your real body is out there still sleeping. If you don't go through a portal, your body won't wake up. That was why I came here."
"The mirrors are for copying, I can feel it. I'm not leaving until I get something to copy." More breaking glass.
"We can come back later? This won't vanish if we leave... Or maybe there is a way I could help? Or we can bring a mirror with us if it is safe?"
Felix... waits... hopefully she won't do something stupid like attacking him.
...No breaking glass. "Woo!"
"Okay, what were you saying, you know how to get out of here?"
"There is a portal. This is a pocket dimension. If you leave you will wake up in your true body."
"Right, well, I'm not opening the front door again. Not after that bear. You can fly, given that you're on the second level?"
She floats upward over the spiral staircase, riding a metal broom-like thing. "Hello. Welcome to my dream, I guess."
"Yes, the wings aren't just for decoration." He follows. "What happened with the bear?"
"It chased me all the way up here on a freaking tree branch and nearly blasted through my door. Tried to climb, failed. Tried to break in, the windows are tougher than they look. It got bored and left eventually." She starts working through the maze. She can tell the mirrors and glass apart more easily than he can, perhaps?
They did mention she could look at magic, so she actually might.
"Wait, the bear was on a tree branch?"
"...No, I was. Witches can fly on anything sufficiently broom-like, so I snapped off a branch to escape."