Tempered Explosive Failsafe

Warforged

You have been equipped with a self-destruct device to ensure your secrets do not fall into the wrong hands while causing minimal collateral damage. As a reaction, when you are reduced to 20% of your hits points or less (rounded down), you may activate your self-destruct device. At the end of your next turn, you detonate into a fiery death. Each creature within 10 feet of you must succeed on a DC 16 Dexterity saving throw or take 10d6 fire damage, or half as much on a success, as your remains are destroyed. Alternatively, this ability activates automatically when you fail your third death saving throw and die.