The Princess of Ortus, the Town of Dead. She also wears a leather gag and is blindfolded, they say she wears it to protect her noble personage from the voices and eyes of the average people. She seems to have strong feelings for Kiriko.
It is revealed that Ulla is known as the 'Idol of Murder'. Kiriko was deceiving her since she was small the same way as the villagers were deceiving Ai making her think that they are actually alive when they're dead. Ulla's eyes killed people when she looked at them, and her touch killed people as well, that being the reason she always wears a mask which covers her eyes. She claims that she knew that her eyes had a certain effect on people, but not that they used to kill people by just gazing at them.
Ulla was born 15 years ago along with her older twin sister Celica. Her mother's last wish at dying moment was for all humans to die. Ulla innocently inherited that wish and gained the power of death. Ever since then Ulla was raised to become the princess of Ortus. And unknowingly to her, she became the idol of murder.