With Lilith as the mother of all humankind from haoxiuyun's blog

Cain is back as D2R Items a character in Diablo 3 as a supporting character. The character of the player, known by the name of Nephalem regardless of which Diablo 3 class they choose The character is requested by Cain's Ward Leah to help save the scholar from the wreckage of Tristram Cathedral which had been struck by a "fallen star.' 

The three suspect that the 'fallen star' is actually a person who they call 'the Stranger,' who has no memories aside from the fact that he was able to lose his sword. The Nephalem takes back the sword that was destroyed into three pieces, but their efforts are quickly stopped by the witch Maghda , who is able to seize the sword shards and captures Cain.

After the conclusion of Act 1 of the highly polarizing Diablo 3. the witch tortures Cain to make him fix the sword using his magic abilities, however he refuses, and is tortured further to levels of death. In an uncontrolled display of power, Leah wipes out Maghda's foes and Maghda escapes, with the Stranger along with her and leaving Leah with an ailing Cain. 

In the final moments of his strength, he magically fixes the sword, unveiling its divine roots, and asks players for the return of the blade to its master. The rest of Diablo 3 is spent avenging Cain's demise and fulfilling his final wish.

With Lilith as the mother of all humankind, returning to Sanctuary, Diablo 4 lacks a scholarly character to guide players on their adventures. Even though the return of the beloved character into Diablo 4 is highly unlikely It wouldn't be unusual to see Blizzard chose to implement it in one way or another. Maybe Deckard Cain will return as buy D2R Ladder Items an entity, or be reincarnated. Whatever the reason, it's to be determined.