Ieyasu Tokugawa, founder of the Edo Shogunate. After his death, he was enshrined as a god and was supposed to have been sleeping peacefully in Nikkou, but for some reason he has transmigrated to the modern period and begun enjoying the Reiwa era with high school girls...!? It's the start of the relaxed modern life of the supreme ruler of the former Warring States period plus high school girls!

(Source: Shueisha, translated)