-1 hit die while wearing 

+1 to all attack and damage rolls 

On a critical hit the wearer does and extra 1d6 damage of the same type, this is 1d10 if the creature being hit is wounded 

Once per long rest the wearer can use an action to damage all wounded creatures within 5 feet, 1d6+Intelligence modifier. This damage done turns into temporary hit points for the wearer. Temporary hit points cannot exceed three times the wearer's level.