Cinnabar

Appearance
Cinnabar is short and chubby. They have dark skin and curly red hair that they wear in a variety of styles.

Abilities

 * Can wield mercury and other d-block metals
 * Levitating sword!
 * Little mercury spirits who are very polite

Epiphany Gaylord
Cinnabar meets Epiphany in Episode X. [more details here]

Aderyn
Aderyn and Cinnabar are first shown interacting in Episode Y. They have a very rocky relationship at first, but eventually they warm up to each other.