15% chance to cast a grand healing spell and flame cloak when below 15% health, 3% chance to conjure a spectral dragon priest when below 15% health.

A really interesting unique item, except the effects so rarely happen. You can't stay under 15% for long otherwise an enemy will grip you into a killcam from 15 metres away.

It should have been something like:
When under 40% health, you have a 10% chance to cast grand healing and flame cloak on yourself every 5 seconds you stay under, the chance slowly increases after every 5 seconds. The summon DP should be the same, when under 40% health every 5 seconds you have a 10% chance to summon it.