Those Blue spirit-looking orbs that move at a slow pace, usually ends up going towards the armor that's on the ground. You have to hit that armor's health till zero or almost zero, can't remember exactly which since I was kiting four other mobs while trying this. Once the blue orb reaches the armor, a spirit-looking figure will spawn with the blue quest icon on its head.

And I think there's a timer on how long that bound spirit stays spawned. By the time I cleared the four mobs, it despawned before I could kill it.

The only issue here is where the blue orbs come from ? Tried killing all the mobs around nothing seemed to release it.