H Seidorei Elf no Souzoku Mondai ni Tsuite

Centuries ago, the founder of the venerable Tatsumiya house received an elven slave from the first Westerners that made shore in Japan. Ever since, the beautiful long-lived Ainalinde was the symbol of power of the Tatsumiya clan, with the head of every generation keeping her as a concubine. In modern times, her libido outgrew the position of a concubine, so she "tends" to every male in the extended Tatsumiya family. And none of them notice that the nearly immortal elven beauty is playing them like a fiddle and weaving a plot centuries in the making...

(Source: 2D Market)