Tsuki ga Michibiku Isekai Douchuu - Extra 19: A certain day at Asora 3

I was a good looking prince when I was reborn, and because I could do indecent things as much as I like, I decided to make a harem while traveling with a beautiful female elf~

After the hard struggle of a post-80s Shen Feiyang, he met with a tragic car accident in his fifties. When he again opened his eyes, he did not see the white walls of a hospital, nor had he arrived at the netherworld. Instead, he had transmigrated into the body of the post-50s young girl, Shen Yunfang.He had transmigrated into an era where people could not get enough to eat or sufficient clothes to wear.Humph, such hardships could not defeat a wise woman who had battled through society for half her life. Watch as she, with a chicken in her left hand and a duck in her right, carries a chubby baby on her back and sings triumphantly along the way.

A supreme expert in the Immortal World had died, and a strand of his soul returned to its original body on Earth. Tang Xiu discovered with amazement that ten thousand years passed in the Immortal World, yet only a single year passed on Earth.

Ruthlessly betrayed by his lover and trusted friends, Tang Xiu found that his soul went back to his previous body on Earth, and, despite he spent 10,000 years in the Immortal World, just a year has passed on Earth and many things have changed. Having an unsurpassed knowledge, Tang Xiu will protect his loved ones and go back to the Immortal World to take his revenge.

- Description from Novelupdates

In the post-apocalyptic age, men were damned.