1. Voice actor sounds nearly identical to 3's Zolton Kulle
2. Zolton Kulle was always "rah rah humanity and nephalem over everyone else." Lillith is a demon outcast. Even though she may be merely using the nephalem, Lillith and Zolton Kulle would have overlapping interests atleast in the short term.
3. Judging by the dialogue "brother against brother" in the gameplay video, it seems as though humanity has descended into an eternal conflict of its own. I'm thinking this dystopian setting, combined with the interventions of Malthiel and Prime Evils prior to Lillith, sets up the reasons for her summoning.
I'm thinking Zolton Kulle summons Lillith to get the nephalem back on its dominant track. I believe that Lillith, though her intentions at this point are unknown, is going to want to restore Sanctuary and humanity to the state she may have originally envisioned, believing it to be corrupted from the Prime Evils' and Malthiel's + Tyreal's intervention. Both Zolton Kulle and Lillith, though their ultimate goals may be different, believe they must go through same means to an end to accomplish said goals. Ofcourse this "means to an end" is likely total scorched Earth and world wide dictatorship, but it would fall in line with Zoltan Kulle's penchant for machiavellianism. Perhaps they aim to reconstruct the world stone, something that requires other dire prerequisite action.
Kull-Aid is but a ghost, and voiced by Wolverine guy.
Guy in the cinematic is either unknown or Rathma, which everyone speaks of. I would love for source material for this dude so it made more sense to me. I lack in lore-know-how these days. I was a lore geek many years ago. If someone could point me to right directions why you think its him, I am all eyes and ears. Thanks!
Isn't Rathma all about the Balance though. Wouldn't bringing Lillith back screw that all up?
Or is he doing it to scare Heaven into opening their doors again?
Yes he is, and he hates Lilith. So it doesn't make much sense it would be him, unless they are about to soft-reboot the lore.
Only thing I know is that he IS one of the first born of Lilith and Inarius, that he feel the humans must be helped, by the darkness. Lilith can save them, but from what is a questionmark, possibly from them self, being all weak and watered-down wanna-be nephalems these days.
He is, what Diablo III 2nd expansion was about to have as an end-boss, a powerful Nephalem. Thats the only thing that can go up against you if you can kill Tathamet (Prime Ultimate Evil), which makes no sense to lore since Lilith among others were trapped in the Abyss at the time, making the ultimate not at all ultimate.
I dunno, there are flaws here and there. If this guy is indeed Rathma, then the story is yet again flawed like crazy.
I'm leaning more towards Malic, considering Malic's soul was once trapped in someones pinky, and the guy in the video is missing a pinky.
Malic probably just took over the entire body after he was presumed "baniashed" to the after life.
Although, it could very well be Mendeln, Who would look like Rathma since he was his disciple, however does not share his hatred of his mother, and strongly believes in Balance, so him summoning Lillith could be to counter something else happening in Sanctuary.
A lot has to do with his eyes being like black shiny stones, and being able to control people's will by staring into their eyes.