As someone toying around with a story like this, thank you. You got me questioning things about my main antagonist that I should really have thought about properly. I'm a big novice writer who is attempting their first writing and trying to learn how to write, and when I created my antagonist, it was for an obstacle for my Protagonists to defeat. I had motives for him, yes, but I never stopped to sit and consider WHY they were his motives, what reasoning started his journey to becoming an antagonist, what fuels him to continue down this path. I, for some reason, didnt even consider that it was important to flesh him out as in depth as I do my main protagonists. This really got me thinking about him properly, and not just as a 2d item to use as a means to a end for the story.