A maiden of the Mermaid people, she is able to change into human form whenever she desires. She was raised to be wary of people but always tries to appear cheerful. Hers is a somewhat sad and tragic life.
A young and cheerful mermaid, Yumei is actually half-human and has the power to take on a human form. Her father, the famous shogun (general) Rijun Koh from Hai-Lan participated in a war against the merfolk, but fell overboard during a battle. Everyone assumed he was dead, but he was taken prisoner by the merfolk. Living among them for a time, he came to understand their customs and even fell in love with a mermaid, Yumei's mother. He eventually returned to Hai-Lan and urged for peace with the merfolk. Despite this sign of goodwill, Yumei's birth was deemed a step too far by her people, and her mother and herself were ostracized by the community. When her mother died, no one grieved, and Yumei herself suppressed her pain, not allowing herself to cry. However, she decided to find her father and tell him of her mother's death, hoping that he, at least, would show some emotion. She also hoped to find the Cerulean Lapis, a legendary stone said to grant the wishes of whoever possesses it.
Pretending to be the sole survivor of a shipwreck, she gets picked up off the coast of Hai-Lan by a small fishing boat, crewed by a father and his son, Fuyuki, who is obviously smitten by the young girl's beauty. As the fisherman returns to port, she asks him about the Lapis, but he laughs and says that it is only a myth. At that moment, the ship starts shaking. Seeing that Yumei is startled, the fisherman explains that it was the ship changing course to avoid the Oouzu, a seasonal shift in the sea currents which can create whirlpools. Upon arriving in Hai-Lan, Fuyuki approaches Yumei and tells her that his father does not believe in the Lapis because he is too old. He, however, thinks the stone does exist, and that you have to believe in it to find it. Encouraged by his words, Yumei asks him what he would wish for if he ever found the Lapis. Fuyuki replies that he would probably want a new ship. When he returns the question, however, Yumei pretends that she has never thought about it.
Yumei asks Fuyuki to help her locate a man by the name of Koh, but is unable to find any information. She thus tells the fisherman she has nowhere to go. He grows suspicious and asks her why she wanted to come to Hai-Lan. She finally admits that she was looking for her father, but, upon hearing his name, the fisherman is surprised. He explains that Koh is dead, assuming that Yumei is the child of one of his mistresses, since she did not know this. Fuyuki, who was eavesdropping at the door, is surprised that Yumei has not been telling the truth, but tries to behave as if he had not overheard anything. The next day, he tells her that he has not found anyone called Koh. She thanks him, but says there is no point in searching anymore. Seeing her grief, he forgets his pretence and urges her not to give up hope: the Lapis could help her see her father again. Upon hearing this, she escapes through a window. As he gives chase, Fuyuki realizes that she is headed for the seashore and, hearing the Oouzu in the distance, fears the worst.
When he reaches the shore, he finds Yumei in the water in her mermaid form. She witnesses his surprise and explains her history. She wanted to see her father and to find at least someone to mourn her mother, but her real wish for the Lapis would have been to be reunited with both her parents, as one family again. However, realizing that her father not only had another family, but that he was also dead, she lost hope and gave up looking. She apologizes to Fuyuki for deceiving him and swims away, not noticing that her tears have crystallized to form the Lapis. Taking the gem, Fuyuki decides to wish for Yumei to be reunited with her parents again, which has the effect of killing her. Lenneth is surprised that Fuyuki's love for Yumei could make him wish for her death, but promises him that his wish will be granted and recruits her.
If Lenneth returns to the seashore after recruiting Yumei, she will remember Fuyuki and find a Fragment of Lapis Gem.
Yumei comes with a selection of attack spells (mainly ice based), but nothing else, so it is a good idea to remedy that if you want her to perform to her full capacity. She is slightly stronger than Jelanda, whose elemental tolerance she shares, but her stats are otherwise identical to Nanami's. Her Familiar is a cockatiel.
As Yumei is a Sorceress, her PWS will vary depending on her assigned attack spell and her weapon. She will either cast the same spell three times in a row or use Great Magic, if her staff has that property. She will say "I hope that wasn't too strong!" before using it.
- Loves Dad
- Never lost
Yumei is one of the characters whose recruitment is randomized. She may appear in Hai-Lan in Chapter 2, 3 or 4, on all difficulties.
Yumei's starting hero value is -41. As the only Einherjar with the Swimmer trait, she is ideal for meeting the Chapter 5 requirements, as she also has the Nimble trait. Nevertheless, she can also meet the requirements for Chapter 4 and 7.
Yumei states that her name means "dream", but despite the fact that she is the Valkyrie Profile equivalent of Japanese, there is no such word as yumei in the Japanese language. Her name would be accurate if the "i" was omitted.
Yumeru, her name in the Japanese version, is composed of the nouns, 夢 (yume, dream)  and 瑠 (ru, precious stone) . The name thus means something like "dream gemstone". 瑠 is notably also used as one of the components in the word for "Lapis-Lazuli" . The name could thus be a reference to Yumei's dream to find the Lapis, or, alternatively, to the Lapis' legendary nature.
- Yumei is voiced by the same actress as Nanami, Llewelyn, Shiho, Celia, Lemia and Claire.
- Yumei temporarily takes on her mermaid form whenever she casts a spell.
- Yumei's mermaid form in-game differs from her concept art: the former has a fishlike tail, as most typical representations of mermaids do, as well as fins for hands, while the latter has legs and human hands.
- Yumei's recruitment sequence tends to be considered as the saddest of all the Einherjar, due to the fact that Fuyuki essentially kills her by wishing for her happiness.
- Since she is a mermaid, Yumei would presumably know about the Oouzu. Her reaction at witnessing it aboard the fishing boat could therefore either be feigned surprise to maintain her disguise, or curiosity at hearing the human name for the phenomenon.
- It is unclear just how Fuyuki's wish allows Yumei to be reunited with her parents, since she is recruited as an Einherjar, and only Einherjar are allowed in Valhalla. However, considering both parents have died some time ago, and that Lenneth herself has only just awoken, it is possible that they were recruited by Hrist before Lenneth's time. The developers have stated that they wanted to include a Sacred Phase scene that showed her being reunited with her parents, but could not do it due to time constraints.
- Yumei is one of Lenneth's more questionable choices of Einherjar, as she does not display any particular battle talents or heroism. The fact that Lenneth recruits her by specifically saying that she will be reunited with her parents actually lends further credence to the fact that they were both made Einherjar.
- Yumei's clothing is the same as the traditional garments of the indigenous Ainu people  of Japan in style and embroidery patterns.