Spirit Surge
Spirit Surge Gem
Empowered Gem - Spirit Surge
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Taking damage has a chance to spawn a ring of projectiles, applying damage-over-time to enemies based on your max health.
— Item Tooltip

Spirit Surge is a universal Empowered Gem ability that works with any class. This ability has a small chance to spawn shadow-like projectiles that can apply a damage-over-time (DoT) effect to any enemy it comes in contact with. The damage of the ability is based on the 25% players current Maximum Health (2.5% per tick). This ability can still be affected by damage boosting emblems such as the Martial and Arcane emblems.