User blog comment:Raylan13/BlizzCon Questions/@comment-176.70.76.65-20131115163923/@comment-4889310-20131115231308

Not to sound like a Spelling/Grammar Nazi, but its Leah *

As for why...


 * SPOILER ALERT!!!*

After Aidan destroyed Diablo in the labyrinth underneath Tristram, due to Diablo's corruptive influence, he had plunged the Soulstone in his head. Adria saw Diablo within Aidan, and devoted herself to serving him in his plan. Perhaps planning for the defeat that he suffers in Diablo II, he and Adria gave birth to Leah, with the intention of her being the vessel for Diablo's rebirth.