Indignant Fetish

Taking damage from any source increases All Damage dealt by 20% and reduces All Incoming Damage by 10%. Lasts 15 seconds.

Random drop on Losomn.

Confirmed locations: Butcher's Quarter, Cotton's Kiln, The Great Sewers, Ironborough, Morrow Parish

Lore

The Fae believe there is a spirit trapped inside this amulet and that its rage at its imprisonment is transferred to the wearer at need.

It does sound like the kind of thing the Fae would do.

"What the One True King did not understand—what no tyrant understands—is that you cannot control a people through force. Eventually, they will harden like a diamond, and you will be crushed by that which you had thought broken."