Help with a Evil Artifacts Abilities and Destruction

[OmNomNid]

So I am planning to run a one or two shot leading up to Halloween and I wanted to do something inspired by popular themes of horror. So I went with the Evil Dead and plan to have the party sealed inside a remote mansion while being subjected to waves of evil laying siege. And the cause of all this turmoil is going to be a artifact called the Vile Heart. It's a ruby, the size of a human heart, that has black, vein like cracks running through it, and if someone listens carefully a heart beat and quiet breathing can almost be heard. I would love some feedback on the mechanics I have devised so far and advice for ways to improve upon my probably sub-par artifact.

Lore:

Long ago there was a nation that turned to the power of sin to forge a mighty empire. Not all the people in this empire were evil at heart however and some began to preach against the course their people were following. One of these individuals was a kind oracle named Huln who peacefully tried to change his people ways. The powerful mages of the empire, who drew upon sin to fuel their empire, grew to hate Huln and sought his destruction. Huln's followers were killed to the last and the battered oracle was left blind and crippled in the wilderness. He would have died had the glabrezu Rallark, having escaped its master's clutches during the attack on Huln's camp, not found him first. Seeing a chance to toy with such a noble mortal Rallark tended to Huln's wounds and cared for him, posing as a orphaned farm girl. As she did, Rallark would constantly try to trick him into making a wish that would let her sow chaos across the lands. Yet for a long time Huln did no such thing. Soon Rallark's whim to toy with Huln turned to obsession and infatuation as she looked for a way to have them wish to be together. Eventually she got him to confess his desires and twisted them as such to her own liking- Huln wanted a way to cleanse the taint from his people's souls- and Rallark gave him the means.

The two become one terrible spirit named Lo that fed off the taint in others and thus saved their souls from the lower planes- yet afterwards Lo would kill them, using the sin it was eating to grow stronger and stronger. The sin-mages grew fearful as Lo grew in power and eventually they combined their might to defeat the Terrible Redeemer. Together they battered Lo into submission and then tore out its heart. Defeated, the mage's lowered their guard and sought to tap into the collected taint trapped within Lo's heart, creating the Vile Heart, never realizing that Lo's urge to consume sin would carry on beyond death.

Description:

The Vile Heart does a few things, none particularly pleasant. First of all the Heart can lay dormant between its uses, but the moment a drop of blood touches the ruby it begins to radiate a evil aura. The aura starts at 1 mile in radius but it grows over time, with each Pulse. The Vile Heart releases a Pulse once per day within its aura's radius, and with each Pulse the aura's radius increases by one mile, to a max of 50 miles. Any creature with a Evil alignment or the evil sub-type that enters the aura instantly knows which direction the heart lies, though they don't learn any information of the Heart itself unless they already possessed knowledge of the artifact. These same creatures must pass a a DC Will save of 10 or be compelled to make their way to the Vile Heart. Those that pass this save are immune to this compulsion effect however this is the only means to gain immunity. Creatures normally immune to compulsion effects must still make a Will save to avoid walking towards the Heart. Mindless, evil creatures automatically fail their Will save and make their way to the Heart. The save DC gets higher as the aura's radius increases, going to DC 15 when the aura reaches 10 miles, DC 20 at 25 miles, and DC 25 when the aura reaches 50 miles.

Creatures in this aura are compelled to act on their vile impulses, furthering their fall into evil. During each Pulse, all creatures within range of the aura must save against the effects of Taint (Heroes of Horror, D&D 3.5). Neutral (N/LN/CN) creatures must save against both Corruption (fort save) and Depravity (will save); failure on either results in 1d4+1 points of taint, though with a +4 to the saves. Evil creatures, while normally immune to the increase of taint, still need to roll a will save to avoid acquiring 1d4+2 points Depravity, though they double their threshold for determining the effects Depravity on them. A successful save for a evil creature still results in 1 point of Depravity. As the Vile Heart causes the taint in creatures to fester instead of causing it, Good aligned creatures and those with the good sub-type are immune to the effects of the Heart. The save DC for these taint effects is equal to the DC evil creatures need to take to avoid the Heart's compulsion effect.

Creatures with a taint score that are slain while in the aura die as normal however all of their taint values are removed; instead that taint goes inside of the Heart where it builds up. Further more, evil actions taken within the aura cause the Heart to acquire 1d10 points of taint. Each time the Heart 'feeds' the vein-like cracks in the ruby convulse and grow darker. Once the Vile Heart has accumulated 1000 points of taint it turn completely black with a red, cat-like eye in the center of it. From that point on the Vile Heart is capable of granting a single wish (one with greater limits than the spell, up to demigod status; it can be used to wish for more wishes, though only three more that act as the spell). To make this wish a innocent (read Good-aligned creature) must be sacrificed within one round of the request. However, before the wish is granted all creatures within the aura with taint are subject to a disintegrate spell as cast by a 20th level wizard; the only difference is that the save DC is equal to 10+the amount of taint a creature has. If this slays the wishmaker the wish is negated and the aura disappears as the Vile Heart goes dormant again. The creatures slain by the Heart's disintegration do not pass on as normal as their souls are bound inside the Vile Heart until the gem is destroyed.

Destruction:

The Vile Heart is very difficult to be destroyed as it requires an almost impossible component. When the stone is full of enough taint to make a wish the ritual must be carried out, however the sacrificed Innocent must be a 'fiend with a pure heart', or as I am setting up one of four things:

-A tiefling or similar spawn with a Good-alignment

-A actual fiend who has done the impossible and overcome their nature

-Someone who is of a Good-alignment but whose soul is bound for any one of the lower planes (such as a CG fighter who owes his soul to a devil or such)

-Or a Good-aligned soul that is/was turned into a fiend through some means

When the Vile Heart is destroyed all of the souls bound within it are freed, all the creatures within the Heart's aura that have taint are panicked for 1 hour and then frightened for 1d4+1 days after that, stopping only to rest when exhausted; they flee from the location the Heart was in when destroyed. Creatures normally immune to fear effects, such as undead, as still effected by this. And finally Lo (the gestalt being of the oracle Huln and the glabrezu Rallark) appears in the closet unoccupied scare the Heart was in, helpless for 10 rounds. In that time Huln manages to wrestle control of the Lo vessel and begs to be slain should anyone be present. After 10 rounds however Rallark regains control and flees, knowing she is too weak to fight and needs to regain strength.

So opinions people? I want something formidable in scope but not immediately all-powerful.