I Was a Bottom-Tier Bureaucrat for 1,500 Years and the Demon King Made Me a Minister Vol 01

In this spinoff story of I've Been Killing Slimes for 300 Years and Maxed Out My Level, enjoy demon Minister of Agriculture Beelzebub's adventures in the days before she met Azusa. After refusing promotions for 1500 years, how did she make it from entry-level office worker right to the top?