A metal harder than iron, more valuable than platinum and less dangerous than gloomium, middium is very hard and light. It is found only in rare seams in the Deep Middergloom, extracting it is extremely dangerous.

When worked by a specialist smith it can be fashioned in armour and weapons.

Middium armour gives an AC of 17 and weighs only 25 pounds, additionally, when its parts touch they make no sound.