Yuusha-sama no Are ga Cheat-kyuu Sugite Komattemasu

Reo is a part-time store clerk. During one of his breaks, he dreamt of a fantasy world where a hero and his aide are fighting against a demon lord, wreaking havoc. The hero was making his retreat when his co-worker abruptly woke Reo. Waving it off as a product of his imagination, Reo continues with his day. Though, thoughts about the hot hero made him horny to which he plans to deal with by hooking up with someone online after his shift ends. Things didn't really happen as planned when Reo encounters the very hero he dreamt about wandering the streets of Japan. Pitying the lost and confused hero, Reo takes him home, where the hero, Adolf, implores Reo to let him stay for a while, to which Reo agrees in exchange for sex. To his surprise, Adolf consents. Now starts the love story of an average store clerk and a hero from another world.

(Source: MU)