Technology in the Cosmic Era can become corrupted and infested. When this happens to a mecha, the result in codenamed a Hekatonkheire.
The Suit of Purity appears to be one designed for the heroic, but it masks it’s true villanous nature. Anyone who wears it for long is bound to be slowly twisted to the Dark Side.
In seeking to escape serving the Lord of Ravens many a hope flickered and died, for those who oppose him end up serving him after all.
A fine suit of armour that provides protection, but from what?
With regard to the plot "Sleeping Mines of Elathon":
You manage to get the water wheel in the mine working which operates a pump to clear the flooded lower levels. As you explore the dank tunnels of the lower galleries, you can hear the creaking of the wheel above. You enter a low-ceilinged passage and are crawling on your backs, when the creaking stops. The water starts seeping wetly around the back of your head...