I Reincarnated as the Bastard Prince? Well, At least I'm OP!

After dying a pathetic death as an overworked office drone, I woke up reincarnated as Archer—the bastard prince of the Brutish Empire. My existence is a royal secret as My father, the King, would rather pretend I don't exist. My half siblings get royal treatment while I'm hidden away like a dirty secret. But I have a secret of my own. I was OP. By age two, I realized monsters flee from my stupidly OP mana. By age ten my mana could level cities—if I dare to unleash it. When my half-sister is kidnapped by the demon king, I finally decided to step out of hiding to become the strongest in this new world.