Kei Sakurai

櫻井螢, Leonhard August, Leonhart
The descendant of a bloodline that allied with the Obsidian Round Table during World War II. She joined the Table to fill the spot left by a member who died eleven years prior. Furthermore as her age contrary to the other members does actually match her appearance she is too young to have met the five highestranking members of the Table. Source: VNDB