Berserker Whirlwind

You swing your weapon around in a circle cleaving all within your range. 

• As an attack action, you may make a whirlwind strike.
• All creatures within range of your weapon must immediately make a DEX save with a DC equal to your DEX score to a maximum of DC 16.
• Each creature that fails this save is hit by your weapon and suffers normal weapon damage plus standard modifiers.
• If the save roll is a natural 1, you critically hit that creature regardless of the final save score. Goliath, Half-Orc, and Orc Barbarians crit on an enemy creature natural save roll of a 1 or 2.
• If all creatures within your range pass their DEX save, you fall prone. Dwarven and Elven Barbarians may make a DC 15 DEX save to avoid falling prone. 
• If you fall prone twice in a row during a single turn as a result of Berserker Whirlwind, you immediately suffer one level of exhaustion and an additional level of exhaustion for each subsequent Berserker Whirlwind that you fall prone from during the battle.