I was Found to Be Competent by a Heroic Female Knight and Lead a Beautiful Harem of Knights

Gaikaku, a genius mage with unparalleled magical prowess, lives in quiet seclusion under the employ of a gluttonous regional lord, Borick. He devotes himself freely to magical research, surrounded by a diverse group of girls from various races. However, after taking down a certain elite elf, his incredible talents as a mage begin to draw attention.