Kertanagara according to the Nagarakertagama
The Nagarakertagama depicts Kertanagara foremost as a devout Buddhist, who kept to the five (Buddhist) precepts (pancashila), underwent a Jina Buddha consecration, and was constant in his Jinabrata (religious observances related to Jina worship). Later in life he became a practitioner of Ganacakra, a term that suggests Tantric rituals which encompassed feasts and activities that were normally forbidden, such as eating meat and drinking wine.
The text is also positive about his political abilities. ‘There was not, so one hears, anyone like the Prince among all the Prabhus [kings] of the past, perfect in sadguna (political accomplishments), knowing the books of learning, versed in the Way of Tattvopadesha (Instruction on Reality)’ (Nagarakertagama 43.4, translation by Pigeaud).
In 1292, so the text says, Kertanagara returned to his divine origins, the Jinendra abode (the abode of the best of the Jina Buddha), and was placed in a religious domain (dharma) in the form of statues of Shiva and Buddha at Singosari.
With his consort, Queen Bajradewi, he became united as an Ardhanareshvari, in this case the Jina Buddha Vairocana with his female counterpart Locana. With his consort Bajradewi he was united as Ardhanareshvari; and with his consort Locana in a statue of Vairocana. According to the text this took place at Sagala.