The Troll Glass

Origin
First documented by Warehouse agent Hans Christian Andersen, The Troll Glass was a key factor in his telling of the story "The Snow Queen". It was said to have been a creation of the Devil, reflecting only the evils of the world. When he attempted to carry it to Heaven to infect the Angels of God with its power, it shattered and it's shards fell all across the world.

Those shards stuck in the eyes of humans, allowing them only to see the worst, ugliest and most negative things. Through unknown means, the Glass seems to have reformed, though spotty record keeping of the era may indicate that the tale is simply a work of pure fiction and the true Glass may never have shattered to start with.

Effects
When looked at, person will see themselves, as expected from a mirror. However this doppelganger has a mind of it's own, and will try and corrupt the viewer by making them doubt themselves and the ones they love. It takes only minutes to warp the mind of the viewer, turning all optimism and compassion into cynicism and hatred towards everything they care about. Given enough time, the effects can be permanent, though quick intervention can save a mind still on the brink of falling.

If the process is complete, the afflicted will be able to perceive only negative emotions, unable to see the beauty or good in anything. This can make them spiteful, hostile and generally dangerous to be around.

If a person is saved from he effects of the Glass, they cannot be swayed by it again. Andersen described this as the "human soul being made a good deal stronger, unable to be corrupted by simple lies and foul tricks".

Agents have noted that the mirror, or more accurately, their reflections, whisper to them when they're nearby, even if the mirror is covered.