So, essentially, his motives are on par of a Final Fantasy villain: This world is imperfect! Ergo, the only solution is global genocide, and position myself as god! I'll make it as beautiful as me!
Meh.
I was really hoping the motives behind such a drastic and extreme action such as "turning every single human into a mindless drone" -- would be more sophisticated. Maybe there's a threat looming, that requires that level of desperation?
I mean, otherwise, why the heck would that noble that raised Helck would even cooperate with the awakened mage? The mage is 1,500 years old and completely nuts, which is boring as fuck, but why would that noble play along? Because he thinks he cannot possibly resist such a being, and he acted to defend his daughter?
......I hate that that's plausible.
Either way, TLDR: I dislike that the mage's motives are so lame. I wanted something more inspiring than "because I'm fucking crazy yo".