Now you gotta remember Diablo and his brothers were not born with soulstones, considering Sanctuary was formed while the three were still in existence. So who or what gave them the soulstones?
Maybe this was answered in the Sin War trilogy, but I haven't read it yet.
Well if you play the game, it is said from Deckard Cain that Tyrael gave the Horadrim three soulstones to imprison the three Prime Evils: Diablo was sealed in the head, Baal in the chest, and Mephisto in the back? Baal's was shattered in an attempt to capture him and Mephisto's was shattered after he was sealed, so it leaves Diablo the only one to remain fully sealed inside his soulstone
And guess what, Mephisto was able to shatter his soulstone into pieces too! He gave the biggest piece to the head of the Zakarum Council and the others to the rest of the council members, thus making his corruption on Kurast without difficulty. Go read your lore
that was Baal's. But with the destruction of the Worldstone Sanctuary isnt any longer shielded by the Burning Hells (or the High Heavens). That comet could be just the start of the invasion. And they already mentioned 7 Lesser Evils (!).
What? Are you on drugs or something, making up lore? Mephisto's was shattered into many pieces, Baal's is unaccounted for since his death. Shows us how much you know
Mephisto's soulstoen wasn't entirely destroyed. It was shatered into many pieces (a dozen I think) and we only destroyed the largest one. If the remainign pieces where to be gathered, then probally Mephisto will gain entrance upon the Sancutary once again and instead of Diablo, HE will be the Harbringer of the Prime Evils return.
Well if you play the game, it is said from Deckard Cain that Tyrael gave the Horadrim three soulstones to imprison the three Prime Evils: Diablo was sealed in the head, Baal in the chest, and Mephisto in the back? Baal's was shattered in an attempt to capture him and Mephisto's was shattered after he was sealed, so it leaves Diablo the only one to remain fully sealed inside his soulstone
Edit: Spelling
What? Are you on drugs or something, making up lore? Mephisto's was shattered into many pieces, Baal's is unaccounted for since his death. Shows us how much you know