Patch reference

When Doom attacks enemy heroes, he applies a curse upon them. After 2.5s, the cursed hero bursts with a pillar of fire, damaging itself and all enemy units in a 66 AoE for 15% of the damage taken from Doom (the hero) over this duration, including damage from the attack that applied the curse. If the cursed hero's level is a multiple of 6, the curse damage and radius will be increased by 66%