The present article sheds a new light on female symbolism in medieval Japanese Esoteric Buddhist visions of kingship by drawing attention to a passage in the Yugikyō that has hitherto passed unnoticed in scholarship. Concretely, the passage concerns an instruction on Kongōsen 金剛染 (S. Vajrarāga) which informs that the latter’s esoteric knowledge symbolically serves as the consort of buddhas, bodhisattvas, and human kings. First, the article provides a discussion of the currently known scriptural sources of female symbolism related to sacred kingship through an analysis of the famous dream of the Tendai prelate Jien 慈円 (1155–1225). It then proceeds with an investigation of an esoteric view of kingship transmitted at Daigoji, which reveals the influence of the cult of Kongōsen. Additionally, based on the fact that Kongōsen was identified with Aizen’ō 愛染王 (S. Rāgarāja), a buddha-mother (butsumo 仏母), the article further clarifies that protector monks visualized themselves as mothers and consorts of the emperor during protective services at court. Thus, by highlighting the concept of enlightenment embodied as mother and consort of divine monarchs, the article provides a crucial new element to better assess the role of female symbolism in esoteric visions of kingship and its relation to the body of the monastic practitioner.