So it came to be that the three Prime Evils were banished in spirit form to the mortal realm and after sewing chaos across the east for decades, they were hunted down by the cursed order of the mortal Horadrim. The Horadrim used artifacts called "soulstones" to contain the essence of Mephisto, the Lord of Hatred, and his brother Baal, the Lord of Destruction. The youngest brother—Diablo, the Lord of Terror—escaped to the west.
From the Diablo IV game files (via the d4data project). Diablo IV © Blizzard Entertainment. Fan site, not affiliated with Blizzard.
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