Rare Wondrous Item (Crown), Requires Attunement 

• You gain advantage on saving throws against being charmed or being put to sleep
• When affected by the Sleep spell, you are considered to have 20 additional hit points for the purposes of the spell. 
• You gain a +2 bonus to Wisdom saving throws for each level of Exhaustion you have. 

Mind-Clearing Pain. This crown has a number of sharp spikes that can pierce into the flesh of the wearer when they are exposed to powers that can affect the mind.
Each time you make a Wisdom saving throw, before rolling the dice, you can take 1d12 magical piercing damage to gain a +2 bonus against that saving throw. This feature can be used multiple times against a single saving throw.
The damage done from this feature cannot be reduced by any way. 

Will of Iron. Once per Long Rest, you can use your action to shield yourself from mental effects for 1 minute. While this feature is active you gain the following benefits: 

• You are immune to being Charmed or Frightened.
• Each time you use the Mind-Clearing Pain feature, you can deal an amount of psychic damage equal to the piercing damage dealt to you by the feature to a creature within 30 feet of you.  
• You cannot be put to sleep by magical means.
  

Curse. Each time you finish a long rest, you must spend one of your hit dice or gain one level of Exhaustion.