Avarice and Generosity

When a life ends in your presence, you’re able to snatch the departing soul, a sliver of its life essence: as a reaction when a creature you can see dies within 120 feet of you, you can cause a soul to be absorbed by the left gauntlet, creating a charge. 

You lose access to the charges created by the absorbed souls if you become unattuned to these gauntlets. You can use the souls with the right gauntlet in the following ways:

•  You have advantage on death saving throws and Constitution saving throws, for your vitality is enhanced by the life essence within the gauntlets.
• When you use a feature that has an expendable resource, such as Hit Dice or Superiority Dice, you can expend a charge instead of its normal resource. The number of charges needed to be expended equal the normal amount of the resource. Any dice that are used normally will still need to be rolled. 
• You can expend a number of charges to cast a levelled spell that you have prepared. The number of charges needed to cast a spell can be no greater than the highest spell slot you have access to. The spell has its normal casting time.
• When you use an item that has charges, you can spend a charge from this item instead. The number of charges expended equal the number of charges the needed normal for the the activation of the item being used. 

Notes: The left gauntlet is an evil-looking thing that resembles the hand of a demon. It seemed to be made out of some sort of black metal, which was covered in twisted thorns. Its fingertips were sharpened into points, and the dirty radiance surrounding it resembled some sort of strange secretion. Just a single look filled all who saw it with a terror stemming from the depths of their souls. In contrast, the right gauntlet looked like the pure, immaculate hand of a maiden. It is white in color and its slender proportions were covered in elaborate gold embroidery, which further emphasized its exquisite beauty. It drew the eye like bees to honey, and just like seeing a world-class beauty, the onlookers felt like they might lose their souls to it.