Feat
Einar's Wrath
The incredible power of Einar, legendary Barbarian
Einar releases a devastating scream. Choose one target and use the sonic damage of the highest-level version of Sound Assault no greater than Einar's character level, treating his character level as Caster Level. The scream uses that spell's damage and counters, but not its area or chance of imposing Disadvantage.
Until combat ends, Einar gains one additional attack per tick, 4 × CHA to attacker Reflex rolls and damage, and 4 × CHA universal damage resistance.
Einar can use this feat only while at 25% of his maximum HP or less, or when one of his friends falls unconscious or dies.