This magic item is made from a mysterious metal from the nine hells. It contains three Infernal Embers 1d4-1 of which are restored at dusk these embers can be ignited to shape shift the Armguard if you use it to shapeshift into one of the battle forms it will snuff out the ember but if you choose a non battle form it will simply use half the ember and the rest will be restored automatically at dusk.

While this Armguard has any of its Infernal Embers, melee weapon attacks made with a weapon held in this hand deal an extra 1d4 fire damage per remaining charge. In addition you can spend a bonus action to shapeshift the Armguard into a battle or non battle form a battle form will last three combat turns before reverting to the armguard and a non battle form can last for 10 minutes and even shift between three different forms within that time.

Battle Forms:

A small shield. While the Hellmorph Armguard is a shield you gain a +1 bonus to your AC and have resistance to damage from nonmagical sources.

A small weapon. While the Hellmorph Armguard is a small weapon it deals 1d6 damage (choose from bludgeoning, piercing, or slashing when the item is formed) and has the finesse property. You are proficient with the weapon and have a +1 bonus to attack and damage rolls made with this weapon. In addition, if the item has any charges remaining this weapon deals an additional 1d4 fire damage to creatures hit with this weapon.

Two tiny weapons. While the Hellmorph Armguard is two tiny weapons, each one deals 1d4 damage (choose from bludgeoning, piercing, or slashing when the item is formed) and has the finesse, light, and thrown (30/60) properties, and you are are proficient with them. You have a +1 bonus to attack and damage rolls made with theses weapons, and they return to your hands immediately after they are used to make a ranged attack.

A small ranged weapon and ammo. While the Hellmorph Armguard is a small ranged weapon and ammunition it deals 1d6 damage (choose from bludgeoning, piercing, or slashing when the item is formed) and has the Ammunition, Range 80/320 properties. You are proficient with the weapon and have a +1 bonus to attack and damage rolls made with this weapon. In addition, if the item has any charges remaining this weapon deals an additional 1d4-1 fire damage to creatures hit with this weapon.

Non Battle Forms:

How Non Battle forms work is you may change the armguard into one small object, two tiny objects or a set of Artisan's tools  when it transforms into the object it gains the properties of the material that object effectively becoming that material in all but appearance while the Armguard is shifted in this way it may shift into different objects with a maximum of three distinct objects per shift 

Notes: Putting it on if attuned to no one if already attuned must kill person who attuned to it