Synopsis
Public Service x 1,500 Years + Pecora’s Magic = Minister of Agriculture
A DEVIL’S WORK IS NEVER DONE!
Beelzebub is a demon of many roles—minister of agriculture, Azusa’s “big sister and the demon king’s closest confidant. Before her illustrious rise to power, though, she was just a low-ranking pencil pusher in the government with no ambitions, no dreams, and no adventure in her life. Then, on a whim of the newly coronated demon king, she received the biggest and most terrifying promotion imaginable! How will Beelzebub handle the sudden responsibilities of the entire Ministry of Agriculture?! Originally published as short stories in the hugely popular I’ve Been Killing Slimes for 300 Years and Maxed Out My Level, the spin-off is back with brand-new illustrations and additional tales from the demon lands!
LN information (LNDB)(.epub)(official) 
Spin-off of I’ve Been Killing Slimes for 300 Years
Genre: Comedy, Fantasy
Volume 01 or (Mirror)
Completed
Password: thatnovelcorner.com
You can read i whenever. The story has nothing to do with the main one, it’s the very definition of a spin-off.
Anyone know if this can be read whenever because is a spin-off “prequel”, or must be read after X volume of Killing Slime because reference future events?
And thanks for the upload
“Between January and July 2018, in the volumes 5 to 7 of the light novel, a special story about the character Beelzebub was published at the end of those volumes. These chapters were later compiled into their own spin-off volume that was released in September 2019.”
From the Wiki.
as much as i would like to respect the release order, it pains me to wait so much for he demon waifu :-/
well, gotta read faster, thanks for the anser, i always forget to check the EN wiki