Amulet of Souls

Physical Description

The amulet is a deep purple diamond inlaid in a black silver ring. The gemstone itself is tiered with a main diamond, then a hole with a 8-pointed-star shaped white diamond inlaid in that diamond. If the amulet contains a soul, the star changes color to match the soul's true nature (lighter shades for more passive and gentle souls and darker shades for malicious souls, and a color that is linked to its "element" (red for fire, orange for nothing, yellow for radiant, green for acid, blue for lightning, purple for psionic, grey for necrotic, brown for earth))

History

The soul of an ancient soul-snatching creature is trapped in the black diamond, and anyone who is in contact with it can hear the creature who, despite their predicament, only wishes to commune with its owner, swearing that, if it were to be released, it would be completely loyal to its owner and all their descendants. The gemstone, however, is nearly indestructible, as it requires a special weapon that must be infused with 20 different, extremely powerful souls. The weapon would be so powerful any creature under that of a god would be unable to wield it and any creature struck by it would instantly die from even a light scratch.

This gem was formed long before civilization took hold, when elementals ran rampant, forming the world. Celestials and fiends were abound, clashing openly and wildly, their blood spilling and mixing into what formed the Soul Devourers, who managed to consume the souls of the fiends and celestials, killing many and eventually separating them into their own dimensions, and any that perished condensed into two gems , one inlaid in the other. Each one was then encased in a ring of silver blended in the mixed blood of celestials and fiends. These gems for the most part were completely shattered, and only three made it.

Abilities

Commune with the Ancient

You may be absorbed into the crystal for varying lengths of time depending on the amount of time you attuned to it. (1 hr: no attunement; 6 hrs: 24 hrs of attunement; 1 day: 72 hrs of attunement; Indefinitely: full attunement) The Soul Devourer inside appears as a human with traits from different races (Orcish teeth, elvish ears, dwarvish facial hair, halfling facial shape, etc.). Every part of it's body is bone white and its eyes are an icy blue. Despite it's off putting appearance, it is extremely friendly and respectful to it's owner and those it considers friends. It sits on a black leather chair in a 50 x 50 foot room that is adorned with a few potted plants, a large table with 8 chairs around it, two shelves, one full of books labeled with years and numbers, and each one is full of a year of information, all of which is what the Soul Devourer learned in the labeled year of it's life. If a soul is contained in the amulet, it is a medium version of it with gold chains around its neck, wrists, and ankles. you may summon any non-living object, though any attempt to leave with it will result in the object disappearing into a small pile of ash.

You may perform one of the following abilities for 1 charge each.

Transfer/Bind Soul (Req. 24 Hours of Attunement)

You may transfer/bind a soul from the amulet to an object or into molten metal. The soul possesses it and anyone within 20 feet can hear it telepathically without being in contact with it. If the object is organic (like a skull), the soul was mixed into the molten metal and made into an object or  is hollow and air tight the soul may be trapped in it indefinitely. If not then it must be a silver cage worth at least 100 GP and the soul may only be contained in the cage for 8 hours. You may exploit a soul (see Soul cage  for exploits) as many times as you wish if it is contained in a hollow or organic object, with the exception of the Steal Life exploit, of which you may only exploit its ES (see below) before it is destroyed and its ES is reduced by however many times you use it. If you destroy a soul in this way, the soul inside leaves a set of gold chains worth about 200 gp inside the room you arrive in when you get absorbed into the gemstone. These chains may be removed from the gemstone without disintegrating.

Enchantment (Req. 72 Hours of Attunement)

You may perform one of the following actions by destroying the soul captured in the star on any object other than the amulet, where the enhancement score (ES) of the creature is 1+(the creature's CR)/2 (round down)

1. make an item an enchanted item that is +(ES)
2. Increase the enchantment of an object by the ES up to +4 and any after that requires a DC 10+(the number of levels after 4) arcana check to enchant, with the enchantment and soul being wasted on a failed save.
3. Attach a specific ability relating to the captured soul with ES charges (Ex. making a branch into a wand of flame with 4 charges from a CR 6 demon soul) that recharge at dawn or with a modifier/effect of (ES/2) (such as a ring into a +5 ring of strength from a CR 18 giant or an axe of lifesteal from a CR 4 undead). 
4. Increase the max number of charges in an item with charges by the ES up to 10 max charges
5. If the ES of a soul is 6 or higher then you may make an object recharge faster (from dawn to long rest to short rest) and if it only takes a short rest to recharge, the you must have a ES 12 soul to make it have infinite charges

Soul Cage (Req. Full Attunement)

You may cast soul cage, where the amulet acts as  the silver cage, and you may capture any type of soul (not just humanoids) however it may only contain a soul for 6 hours and you may only exploit the soul 4 times before the soul is released. Exploiting a soul does not drain a charge. If the creature is a spirit on its own (such as a banshee) then you may cast it at any point without waiting for it to die, however it requires an action to do so and the spirit may attempt a DC 17 Dex or Wis saving throw (without advantage) and the spell fails on a successful save. 

Notes: week (168 hours of attunement) to unlock all abilities (unless willingly gifted from someone who has fully attuned it, in which case it requires a short rest spent with the two together the entire time)