Hello Im playing D3 on Xbox One in Adventure mode. Sometime I have a black icon with a skull inside apearing over my health bar (beside the orange orb) with a number inside . Whats the meaning of this icon?
Are you a Necromancer? Is it perhaps the Command Skeletons or Skeletal Mages skill telling you how many you have out?
No I play the barbarian. Im playing the adventure mode in Torment IV difficulty level. Its a black square icon. With a gray skull inside. In the lower right of the square , theres a number. 1,2,3 or 4. The number seem to increment when Im in battle. But I cant tell when the number goes UP. When the number is at 4, the next time the number increase, the icon disapear. It reappear when I start another battle.
EDIT: Ok I finally found the answer. Its the number of skelettons I have summoned by my sword as a sidekicks before my sword is blessed with flames power.
FACEPALM 
So, that’d be the Corrupted Ashbringer then…
Chance on kill to raise a skeleton to fight for you. Upon accumulating 5 skeletons, they each explode for 1000% weapon damage and the sword transforms into Ashbringer for a short time. Attacking with Ashbringer burns your enemy for 5462% weapon damage as Holy. [5000 - 6000]%