Frozen Turtle Shell

Nothing happens while you are healthy. The shield only spins up once you have fallen to half life or below, and from that point it shaves a quarter off everything that reaches you. That makes it an accessory for fights you expect to survive badly rather than cleanly: long attrition bosses, the harder invasions, anywhere you spend real time sitting in the red.

It works against a build that keeps you topped up. If you run heavy regeneration and drink healing potions the moment they come off cooldown, you may never dip low enough to see it activate, and the slot would do more with flat defense.

It is also a component. Combining it with a Paladin's Shield gives you the Frozen Shield, which keeps the low health barrier and adds everything the paladin item already did, so most players stop wearing the shell on its own once that becomes possible.

• It is called a turtle shell and comes off a tortoise, which is a quirk the regular version shares.