I heard the speech on the roof, yeah, that speech was clear as day.
First he goes devils, then he goes to Gods, and then he creates something too powerful he has no control of, that should be more powerful than Superman, he creates a devil of his own doing using his own blood on the corpse of the guy who wanted to kill him and every other human on the planet then places it in the regeneration matrix, and with no means to control it.
Killing that guy he feeds candy in his own house is random and not matched with his motives.
Hey Superman, I will kill your mom if you don't kill Batman, who I won't tell you that I want him to kill you, then I will kill your mom.
Alexander Luthor in a nutshell =