Mirror of Darkness
From Ultima Codex
Ultima IX in the Guardian's fortress, and is roughly three meters high. It appears to be a spying instrument of the Guardian, as it enabled him to see far away places (but not everywhere, as Stonegate was protected from its view of the Time Lord). The mirror later showed the Avatar the destruction of the city Skara Brae at the Guardian's orders. It was destroyed in the end, when the Avatar cast Armageddon, dissolving it into nothing.
- In the original plot, both mirrors had more of a role, as the Guardian used his mirror to send Lord British horrible visions through the other mirror while he's sleeping, in order to set him against the Avatar. Thus why the player gets points when breaking it, since it would end this manipulation. Thus the mirror in the bedroom is an artifact left over from the original plot, as it no longer made any sense in the new plot.
- Using the mirror in-game (both of the mirrors do) shows the Armageddon video.