Azura's Star

An eight-pointed crystalline star with a metal casing. It pulses with a hungry energy. 

While attuned to this item: 

• Upon reducing a creature (that isn't a construct) to 0 hit points while within 30ft of the creature, you may choose to trap its soul inside the Star, instantly killing the creature
• Only one soul may be trapped inside the Star at a time 
• As an action, you can consume the soul currently held inside the Star
• The soul you consume gives you a spell slot of a level either based on the creature's challenge rating, or at the DM's discretion
• The Star cannot grant a slot higher than your highest slot level, instead granting a spell slot of that level. 
• Alternatively, you can perform a 1 minute ritual to purge the current soul from the Star, allowing you to trap a different soul inside. 
• You may only consume a soul from the Star once per long rest. 

If a Warlock is attuned to this item,  the Star can only grant them a spell slot of their current slot level. Consuming a soul below this level has no effect. 

A creature whose soul has been consumed (not purged) using the Star cannot be resurrected by any means short of a Wish spell. 

Notes: Daedric Artifact, by a Spellcaster