This is a tough one. having not read to the end yet, this 'real or imaginary' concept puts a heavy assumption in the readers head. The chances that two galactic young leaders suffering from delusions are slim so from reading this I would think God obviously has a hand in this, that there is some kind of cosmic master plan at play here, beyond the understanding of human beings. As a scifi reader I'd be looking for something like this. This story promises this. The title promises this. In the synopsis you lay out a major plot twist, and a scifi reader like me could feel that they might be cheated if they invest in this story. This could be end up being about mental illness and not about high cosmological/theological concepts, or left open ended.
I have a question that will help me better understand how to approach this.
Without spoiling the details in final act of the story, have you made a decision on whether these boys are both delusional, or is God real in the Biblical sense, real is a high scifi conceptual sense, or is one delusional and the other not?
I address the chances of two young leaders having mental illness, beginning in chapter two, where I introduce the boys at various ages. I introduce God in Joseph's head at age 4 in 4005 AD. I introduce God in Apollo's head at age 7 in 4010 AD (Joseph is two years older than Apollo). I also establish that Joseph and Apollo are royal cousins (Empress Elizabeth is the sister of Queen Mary). Finally, I explain that mental illness runs in both families. My goal is for the odds of mental illness vs real God to be 50/50. I then walk a drunken line between the two possibilities, having fun throwing out clues one way, and then the next. It's a trilogy and I won't reveal the true answer until the end of book three, but I already know how I plan to end it. However, it's a long way to the end of the third book, and I may think of an even better ending.