Overdrive

With this feat you can cast Haste (Target: Self), without expending a spell slot or needing to be able to use spellcasting. When you cast Haste using this feat, cast it as a bonus action. In exchange when the spell ends you gain one level of exhaustion. If you use this feat again while exhausted you ignore all levels of exhaustion until the spell ends. If you use this feat while at 5 levels of exhaustion you double your attack and damage modifiers. When this haste cast at 5 levels of exhaustion ends, you explode dealing 8d6 fire damage in a 20 foot radius, and your body is destroyed preventing revival, unless a wish spell is used.