I'm the only WHAT!? (Male Kaiju Reader x Kaiju Girl Harem)

In the future where humans have almost destroyed themselves in nuclear war the last of the humans came together and started living in the mountains in isolation but Monarch continued to operate, while the titans roamed the earth, and continued fighting for dominance, but their was one small problem they were all females, their were no male titans around anymore. They had all died out, but then another titan awakened, but not just any titan... a male titan.