A lantern that shines with blue flame, inside it’s victims souls can be seen.

As an action you can place your hand on the lantern and move your soul inside. When inside your body experiences the effects of sequester and your soul can leave the lantern and return to the body at anytime. 

you can spend an action to try and steal the soul of an unconscious enemy. When doing so they make a wisdom save of 15 and if they fail their soul enters the lantern. If they succeed they are immune to the lantern for 24 hours. When put into the lantern in this way a person outside the lantern must let their soul escape for them to return to their body.

in addition it has charges equal to 10 times the souls inside of it. You siphon away some of the soul’s essence and gain 1d10 temporary hit points. This costs a charge and removes a tenth of a souls health