Blackcurrant

Blackcurrant (ブラックカラント, Burakkukaranto) is the benevolent overseer of Rakyuo, and bears a strong resemblance to a Darkness Seirei.

In Magical Vacation
In order to get the Veil of Darkness, the students of Will-o'-Wisp disguise themselves with the Veil of Light. This allows them to communicate with Rakyuo's Stars and help them ascend in order to reach Blackcurrant, who waits in the cave's furthest reaches. He states that he is born from, and gives birth to the Light.

When interacted with, Blackcurrant explains how the students are beings of Light, while Enigmas are beings of Darkness, and that Light and Darkness will be one in the same some day. There is no boss fight against Blackcurrant; instead, he grants the students with the Veil of Darkness. With it, they can enter the Corridor of Death in order to catch up with Candy and Ganache.