Torturer was ported directly from DotA's Tormented Soul with one exception: the Impalement received a 25% nerf! Here are the two spells:
Deals 9.375/18.750/28.125/37.500 damage every 0.25 seconds for 8 seconds, total of 300/600/900/1200 damage.
Tormented SoulDIABOLIC EDDICT
Deals 12.5/25.0/37.5/50.0 damage every 0.25 seconds for 8 seconds, total of 400/800/1200/1600 damage.
Even in its original form, this spell was very situational because the damage was severely hampered by nearby creeps and the high armor of heroes late-game. I suggest buffing the current damage of Impalement by 33% so that it remains at least as useful as its mirror spell in DotA.