According to scripture Zi-bu-yu in Qing dynasty, Hua Po is a kind of tree spirit said to be formed from the disembodied souls of dead humans when three or more people hang themselves from the same tree. They appear as beautiful young girls that are dressed in white clothes but are much smaller than the average human. Although they cannot speak, it is said that they make sounds that are as beautiful as those of songbirds.
"A tree spirit of Chinese legend. They are said to be manifestations of the resentment and regret of those who commit suicide, springing from trees where three or more people have hung themselves. Hua Po appear as pure, young maidens with white clothes, small enough to fit in the palm of your hand. Their bodies are hairless except for their heads. Their voices resemble the sounds of songbirds and as such they cannot converse with humans. As tree spirits, they cannot live without water. If not given water, they will shrivel up and die. Giving water to a dried-out Hua Po, however, will restore it to life."
—Shin Megami Tensei IMAGINE Compendium
Hua Po are a regular spawn in Suginami and Shibuya fields, as well as the Shibuya Quartz instances. She is one of the mount-capable demons and features regularly in Oboro's Interaction Time System quests.
"A tree spirit of Chinese folklore who dwells in trees used for hangings. She is smaller than a human, and cannot speak, but her voice is said to be as clear as a bird`s song."
—Persona 3 FES Compendium
Hua Po is one of the exclusive Personas that have been introduced in Persona 3 FES. She can only be fused after obtaining the Small Cheongsam from taking Elizabeth to Paulownia Mall. Hua Po can also be fused by Aigis in the playable epilogue, The Answer, without this restriction.