Mirror of opposition (painted black)

[MercuryAlloy]

I wonder how does the mirror of opposition actually works.

For example, if I painted its surface black, does that mean that my duplicate can't walk through it anymore?

Does duplicate has any mind to plotting against me, if I ran away from it? Does it actually need to sleep?

Were there any story in endless Magazine and books about the mirror creators, purposes or at list why duplicate what to kill you?

How long will the duplicate exist and how will it act if the creature with no attacks at all (such as a toad) or the one that completely immune to all its own attacks (fire elemental) will look in the mirror?

Will it work on Golem? Will it work on duplicate?

Will new duplicate retain all conditions I had, when I look in the mirror?

If I stand alone in front of it, does that mean that all 4 charges of the mirror will be used on me and I'll doing with 4 duplicates of me now?

Is there any connection with the Plane of Mirrors?

[Khedrac]

You need to re-read the item description:

Mirror of Opposition: This item resembles a normal mirror about 4 feet long and 3 feet wide. It can be hung or placed on a surface and then activated by speaking a command word. The same command word deactivates the mirror. If a creature sees its reflection in the mirror’s surface, an exact duplicate of that creature comes into being.
If you paint the mirror black then then no reflection of any creature is formed and creatures cannot see their reflection = no duplicates.

The adventure Expedition to the Ruins of Castle Greyhawk features mirror duplicates of Gary Gygax's original campaign party that have been trapped outside of their home dimension. Now I think the original party encountering them and visiting their home dimension is probably true for the original campaign; but that would have predated the invention of the plane of mirrors so whilst there might be a link the adventure provides a strong suggestion that there is not one (the duplicates don't come from a conventional mirror of opposition so we cannot be sure).

The duplicate created is a duplicate - it has all the intelligence and capabilities of the original at the time of creation (so will include buffs and debuffs etc.).
It will also fight as intelligently as it can.
The item description makes no comments for other creature types, but the requirement is for the creature to meet the gaze of its reflection - so that is what determines if a duplicate is created.

As for whether one can end up fighting 4 at once - DM's call.
I would rule that while your duplicate is out of the mirror fighting you you cast no reflection - other people could create more duplicates, but you cannot until your duplicate has been killed.

[MercuryAlloy]

I'd actually thought to paint it the round then I see it with something like prestidigitation or throw out the bucket of paint.

I know that there is no rules for these kind of situation in the core book, but I may be you have some kind of homerules or ideas?