Lord of Hatred
Second Brother of Diablo (Satan)

Mephisto was the first Prime Evil to be captured and his stone was buried in a vault beneath the Aranoch desert. A third of the Horadrim stayed to guard this tomb until the remaining two Brothers were captured. Though the cost was high, all of The Three were eventually captured.

Mephisto finally managed to overcome the powers of the Soulstone that imprisoned him enough to influence and corrupt the local priesthood, known as the Zakarum. The Demon then had the priests work spells to shatter the Soulstone into seven shards, breaking the mystic seal and freeing the Lord of Hatred. Mephisto drove the six smaller shards into the left palms of six Zakarum archbishops who were then charged with bringing him nourishment in the form of human sacrifices while running their temple. The largest stone pierced the hand of the Que-Hegan, the highest divine authority of the Zakarum faith. It was this body that the Demon used as his manifestation on the mortal plane, warping the mortal’s form into an approximation of his true visage. For years the corrupted religious leaders of the Zakarum have kept Mephisto supplied with information and misguided followers to carry out his plans of conquest.

Diablo II - amazing game.