- Unlocked at Siphoning rank 20.
- U6: This ability no longer affects attack speed. In addition, if your target dies while affected by Debilitate, the cost of the spell is refunded to you. 
- U9: This morph now also allows you to place Debilitate on an unlimited amount of targets. 
- U9: Reduced the Magicka refund from this morph to 50% of the ability's cost from 100%. 
- U6: Fixed an issue where the Synergy (Purify) for Cleansing Ritual wasn't removing the effects from Crippling Grasp. 
- U4: As of Update 4, this ability no longer removes the Nightblade active skill, Shadow Cloak 
- As of Update 5, using this ability will no longer reveal you if you have Shadow Cloak activated. 
- U6: Increased the damage dealt by Cripple by 6%. 
- U7: Updated the tooltips for Agony and Cripple to properly state they can only affect one target at a time. 
- U8: A number of abilities, including this one, will now properly display "Target is Immune" messaging if a target is immune to a component of the ability: 
- U8: Fixed an issue where several damage over time effects were not allowing multiple casters to apply their own stack. For example, previously if two player characters cast Scalding Rune at the same target, only one of those effects would apply damage over time to the target. This is now corrected for a number of abilities, including this one.