Eruruu (エルルゥ) is Aruruu's older sister and Hakuoro's main love interest. It was she who found Hakuoro and healed him back to health in the beginning of the series. She gets her name from the Eruruu Flower.
Eruruu is a rather beautiful young woman with wolf ears and a tail. She has big brown eyes, pale skin, and dark grey hair. She is short for her age, as she is quite a bit shorter than Hakuoro. She is often taunted because of her small breast size. She wears her hair in a low pony tail, letting her bangs and random pieces of hair hang freely. She also has a hair piece which happens to be an important key. Eruru's clothing consists of a high-collared, ankle length dress with long sleeves and short brown boots
Eruruu is a strong-willed and emphatic person who puts all her heart and effort into the things she does. She could be described as having a forceful, but caring personality. She is a kind hearted person who loves helping people and hates to see someone get hurt. Eruruu is protective over her younger sister, Aruruu, and often scolds and/or worries about her. During the series, Eruruu conceals her feelings in an attempt to keep everyone happy, especially her feelings for Hakuoro and her grief for her grandmother's passing.
After helping Hakuoro in his recovery, Eruruu begins to fall in love with him due to his will to protect and of his care for her sister Aruruu. She sticks by him throughout their many adventures and becomes his personal servant when he becomes emperor. In the end, she eagerly waits for Hakuoro to return from his sleep and continues to be a healer.
For some time, Eruruu was quite well-known across Tuskur as a prominent apothecary, but she suddenly disappeared from the world one day.
Eruruu is re-introduced in Utawarerumono: Mask of Truth as one of Kuon's "mothers," and someone especially important to her. She currently resides in the Onkamiyamukai Subterrane Shrine as a priestess, watching over the seal where Hakuoro is located.
Nuwangi - One of Eruruu's childhood friends. He is obsessed over his nonexistent relationship with Eruru. Nuwangi claims that she supposedly promised him that she would marry him.
Aruruu - Eruruu's younger sister. Eruruu often displays her fear for her sister's safety in the form of scolding, but it is clear she loves her very much.
Hakuoro - Eruruu's only love interest throughout the series, she shows her unhappiness when he often refers to her as his younger sister. One large reason she fell in love with him was his treatment of her sister. Not rejecting her when she "adopted" him as her father and filling that role in her life. At the end of the series, the two confess their love for each other and Eruruu waits with hope that Hakuoro will return.
Kuon - Along with the others, Eruruu raised Kuon when she was a child. It is likely that Kuon may be closest to Eruruu of all her mothers.
- Eruruu is highly skilled as an apothecary, and it was she who who taught the medicinal arts to Kuon. Her teachings were strict when compared to other general topics, but Eruruu had learned well from her grandmother: an apothecary's work is a serious matter, as others' lives may rest in their hands.
- It is also likely that she taught Kuon the same song she used for Hakuoro when Kuon sang it in front of Haku. Based on these facts, it's likely that of all the mothers Kuon is close to, Eruruu is the closest.
- Eruruu is the reincarnation of Mikoto, Iceman's wife.