Wow, his train of thought was so dumb. Historically humans and elves have never had children, okay, but he believes the doubts in his mind over his family or the kingdom he's built? Does he not have faith in his subjects? And then when he does take action, the first thing he does is stab his partner? Huh? From the queen's point of view he just grew more irritated until he snapped and stabbed her. So he trusted the "evil god's whispers" over this partner he has presumably spent years with?
And then, after he kills everyone in his kingdom, he comes back as undead, which is unfair, but then his first thought is "I must assimilate all other nations into mine, by force if needed"? He wants to drag everyone else into his misery? And he decides to blame all gods for his fate, even though this was just one evil god? It could even have been just an evil wizard using telepathy to trick him. This backstory just feels like a child with power, throwing a tantrum.