Mask of Implacability (Dragon Quest II)

Protects the wearer far better than any other mask, but does require them to put up with an inconvenient curse.

This is a helmet.
It dramatically increases defence when equipped, but also keeps the wearer in a permanent state of confusion.
This item is cursed, and will not be easy to remove once equipped. Be careful!
Selling such a precious item would be a waste, but it should fetch a price of 1 gold coin.