Uses for Souls

Where would you even get that many souls from? Do like, ALL souls get trapped in there on death? Does the afterlife even still accept new intake or does the soul stone grab them all before they can petition at the pearly gates?

Eat it. Bring it into your being. And save those souls with your own. Become their god and deliver them rest.

Or fuck I don't know explode into flesh and terror I don't know how these things work.

You represent the Church correct?
Try looking for any scrolls, manuscripts, documents, or even local legends about the stone, it's soul-keeping properties, or perhaps the necromancer who made it.
If there is anything written down, it will probably be held in the Church.

As for "alternative" purposes, it contains an unnumerable amount of souls; sounds to me like you are carrying the start of a motherfucking ghost army in your pocket.

From what we've gathered so far, the Stone was created 1500~ years ago, during the reign of King Bellophant of Feldannr, before his ascension to Ansuzhood (Demigodhood).

Most people know Bellophant as a heroic king who was wise and just. However, we've discovered that he was actually a powerful necromancer who protected his people with armies of the undead. After his death and subsequent ascension, there was a civil war in the region over whether or not to worship the new godling. It ended with the people deciding to bury the truth, and worship only the aspects of him that they liked.

So as far as we can tell, Bellophant, the Deity that I worship, created the stone. It might store the souls of the countless enemies he destroyed, it might store the soul of everyone who died while he lived. It might be the afterlife of anybody who worships him. We DON'T KNOW.

The worst part about this is the fact that the religion of the land isn't centralized for the most part. The only really centralized and structured sect of the faith is 'Fylkirate' and they believe that the God of the Hearth has been incarnating himself as the mortal emperor of Kaizare for the past thousand years. I am decidedly NOT a Fylkirate, I am an ansuzian. I worship the Gods and the ancestor heroes that came after them.

It's the phylactery of Bellophant's advisor, I fucking guarantee it.
Eat it.

It's the afterlife for your religion. Calling it now.

You should find a way to communicate with the stone.
If it is indeed Bellophant's Grand Army (tm), or his people, you could usher in a new age of your God's glory.

If it's his enemies kept in there, destroy it, so the secret of your God's true nature dies with you.

Pic
Oh your god made it? Fucking eat it.

Stick in a magical cannon.

Summon a representative of the god of death/afterlife and turn in over to them and hope for an appropriate reward.