I would also like to mention that I think the lesser evils are also interesting and should be in the spotlight. I understand that the main evil is the focus, but also characters like Azmodan and Belial, who were particularly interesting in Diablo 3. The two had their own agenda and had personality and character. This is what I hoped for from Duriel and Andariel in Diablo 4. But in the end they were portrayed like random demons who had no character and didn't even speak. I hope Azmodan and Belial aren't treated like this!
What are they talking? Mephisto is dead. I destroyed his soul stone in Diablo 2 and got some Pul Runes. More dead can no other prime evil be.