Lionhearted Helm

Wondrous item, very rare (requires attunement)

While wearing this helmet, you gain a +1 bonus to AC, and you have advantage on saving throws against being frightened. In addition, at the start of each of your turns, if you lost any temporary hit points since the end of your last turn, you regain 1d10 of them (to a maximum of the amount lost); you must still have at least 1 temporary hit point to regain any in this way.

The helmet has 5 charges for the following properties. It regains 1d4 + 1 expended charges daily at dawn. You must be wearing the helmet in order to use its various properties.

Frightening Roar. Once on each of your turns when you take the Attack action, you can expend 1 of the helmet's charges and forgo one of your attacks to release a thundering roar, which is audible out to 120 feet. Each hostile creature that can hear you within 10 feet of you must make a DC 16 Constitution saving throw; this effect's range increases to 20 feet if you're in werelion form (see below). A creature has disadvantage on the saving throw if it's frightened. On a failed save, a creature takes 3d6 thunder damage and is frightened of you until the end of your next turn; a creature that fails the save by 5 or more is also knocked prone. On a successful save, a creature takes half as much thunder damage and isn't frightened.

Werelion Form. You can use a bonus action to expend 2 of the helmet's charges to physically change your form to resemble a werelion in hybrid form. You immediately gain 30 temporary hit points, which last for up to 1 hour or until you're no longer in this form. While in this form, you have advantage on Wisdom (Perception) checks, and you can make unarmed strikes with your teeth and claws, dealing piercing or slashing damage, respectively, instead of bludgeoning; these unarmed strikes use a d6 damage die, unless it's already higher. Your statistics are otherwise unchanged. You remain in this form until you have no temporary hit points remaining or until you end it early as a bonus action.

You peer down into this den, made not by gods or time, but by the hands of man. A glorified cage, meant only to permit the weak to observe the strong: the king of cats.
For entertainment, you say. Ludicrous: we are royalty, and heed not the misplaced posturing of jesters. Our reign began before your time, and it will persist beyond it.
Know this, human: long after your hubris has flattened the very towers you built, our roar will ring out true and proud, undeterred. Our hearts beat bravely, and our might is tireless.