Here’s an item my PCs might discover next session, based on (or, more accurately, stolen wholesale from) the manga Berserk:
Berserker Armor 3 armor, worn, clumsy, 4 weight
A suit of blood-stained black armor that allows its wearer to fight on past normal limits by nullifying pain. When you’re reduced to 0 HP but not killed outright (eaten by a dragon, stepped on by a giant, etc.), you may instead bump yourself up to 1 HP and delay taking your Last Breath until the end of combat. When you take your Last Breath, take -1 to the roll. You may delay your Last Breath up to five times per combat, taking -1 to the roll each time you do. If you delay a sixth time, you automatically fail your Last Breath.