Eminence in Shadow

You're playing as Cid Kagenou, a young noble with an older sister named Claire. This is based on an anime series that came out recently (light novel as well as manga too). You wield atomic energy in a fantasy setting because the character achieved his dream of being able to survive a nuclear explosion... in a fantasy world with nothing remotely close to nuclear power except maybe magic. I saw there were several adventures attempting this and decided to have a crack at it.