So I've just started worldbuilding and am having a great time. I've begun work on the dwarven king and decided to make his crown first. I'm wondering what rarity it should be and how balanced you guys think it is or what I should change as I'm completely new to this.

Crown of Mental Defense - (requires attunement)
-While wearing this crown you are immune to magic that allows other creatures to read your thoughts, determine whether you are lying, know your alignment, or know your creatures type. Creatures can telepathically communicate with you only if you allow it.

-While wearing this crown you are immune to being charmed or frightened.

-While wearing this crown you are immune to mind altering effects such as suggestion and command.

-If you die while wearing this crown your soul enters it, unless it already houses a soul. You can remain in the crown or depart for the afterlife. As long as your soul is in the crown, you can telepathically communicate with any creature wearing it. A wearer can't prevent this telepathic communication.

The idea behind the crown is to provide some form of Mental Defense for the king who is a paladin/fighter and thus weaker in the mental department. And if he does end up dying then he can communicate with his successor or murderer or what have you. Quite a bit is stolen from the ring of mind shielding which is an uncommon. This has extra bonuses though which makes me think its rare quality. Thoughts? Suggestions? Help me out! Also if you have any cool ideas for armor, shield, or mace for a dwarven king let me know!