I’m glad you asked this cause I have an explanation to the magic of the mirror. It’s kinda long though so

First off, I believe for there to be three denominations of ‘not normal’ things

• magic
• paranormal
• super powers

It’s kinda like how you wouldn’t say that Harry Potter has super powers or that the X-Men are paranormal. HP is magic and X-Men are super.

These things rarely overlap. Ghosts aren’t magic. Super heroes aren’t paranormal, and wizards don’t have super powers.

Now, back to The Mirror of Maturity

The mirror is magic. It has the magical ability to not necessarily show people in the future actually, but what they will look like when they’re older. This is why the mirror still works like a mirror, reflecting Arthur and Vivi’s movements. If it showed the actual future, it would be more like a window showing you what you are doing in like 10 years. Eating cereal, shopping, etc.

Now, magic can get confused and mixed up. It has an unspoken science to itself. If something that doesn’t correlate with how the magic works and comes into contact with it, there will be different results.

This is where Lewis comes in.

Normally in the case of 'died young’ folk, the mirror will show a person what they would of looked like right before their death, if their death was recent enough to cut off its general time-jump (which is roughly 10 years or so, it’s a little different for everyone)

But Lewis came BACK to life; he was undead after death. This is what caused the mirror to be confused. It recognizes that Lewis is alive after death, but it’s not Lewis as he should be. Aka, human.

So, it caused the magic to get mixed up

And instead of being a reflection of alive Lewis, seen only to younger Lewis

It broadcasted Lewis’s future self to the room, reversed of what it normally does.

Because, when you die, you don’t see your death.

Only other people do.

And that’s why Lewis didn’t see anything, while Arthur, Vivi, and Mystery saw future Ghost Lewis.