Shadow of Styx
Helcurt remains in Prowler state until spotted by the enemy team, gaining 15% extra Movement Speed, and continuously regenerating (+30% Total Physical Attack) HP if he has not dealt any damage. He gains 50% extra Attack Speed and 50% extra Movement Speed (decreasing over time) for 4s upon being spotted and leaves Prowler state 0.75s later. Any hero killed after being hit by Helcurt leaves a dark fog that explodes and spreads with a cooldown of 10s. Helcurt Conceals himself while within the dark fog.

Hidden Terror
Deadly Stinger
Dark Night Falls