With upcoming monk changes I think it's worth bringing up and pointing out that this ability is still rather broken.
It does a 1d4 level drain on the target and then, if the target is slain within 10 seconds, an area 1d2 level drain on enemies. The tooltip specifies "enemies", but the affect hits everyone - hirelings, yourself, group mates, etc. in range.
This is a pretty long-standing one and with the monk adjustments coming up it'd be real nice to see this one fixed It's a bit hard to justify ever using as is, considering the stacking self-leveldrain it can cause, not to mention the ire of groupmates!