Dayu

"Better watch what you say. If it wasn't for Master Xandred where would you be?"

- Dayu to Rofer

Dayu (formerly known as Dahlia) is a Human/Nighlok and one of Master Xandred's two followers, working to bring the Netherworld onto Earth by flooding the Sanzu River.

Background
Prior to her service to Xandred, Dayu was once a woman named Dahlia, recently married to the man known as Deker. On the night of their wedding the two presented each other with gifts; a Katana for Deker and a decorated guitar for Dahlia. Sometime in the night a fire broke out in their home while Dahlia (and presumably Deker) were asleep, when Dahlia woke to find their bedroom burning, Deker was nowhere to be found. The couple managed to escape the house, but Deker was severely injured.

In a moment of desperation she called out for help and summoned the "King of the Nighlok's" (later revealed to be Serrator). Serrator agreed to save Deker, but at the expense of Dahlia's soul. She agreed to his terms and was tricked soon thereafter, Serrator turned them both into Nighloks and wiped Deker of his memory. Upon Deker's revival and immediate transformation into his Nighlok half, he vanished, leaving Dalia behind. Its assumed that Dahlia joined Xandred shortly afterward and became known as Dayu.

As a half-Nighlok, Dayu served as one of the two generals working at Xandred's side to fight against the Samurai Rangers, yet she is embittered by her time in the Netherworld. Dayu still clings to the memory of her mortal life and her relationship with Deker, despite that he has no memory of their life together. She primarily regrets "cursing" him as a Nighlok with the unquenchable desire for the "ultimate duel". On one occasion, she attempted to use the tears of newlywed brides to flood the Sanzu River and recreate her wedding dress, only to be foiled by the Samurai Rangers (Mia and Emily in particular).

She is skilled in battle, lasting long enough against the Rangers until Jayden prepared to attack her with the Fire Smasher. It was there that she was rescued and forced to retreat by Deker, who intervened in the battle upon finding the opponent Uramasa (his Katana) was seeking. She thanks him for saving her life and inquires why he wishes to fight the Red Ranger, to which he answers he is "cursed to satisfy this urge" for the ultimate duel and nothing else was important, not even his past life.

When visiting The Tengen Gate, Mia and Kevin were told of the old folktale about a woman who made a deal with the King of the Nighloks to save her beloved and was tricked, foreshadowing the fate of Dayu and Deker. When Xandred damaged her Harmonium, Dayu fled the ship, intending not to return. She attacked a guitarist performing for the public, intending to use him to repair her weapon. This incites a battle between her and Mia, who happened to be passing by when she attacked. Xandred sends Rhinosnorus after Dayu, the monster blasts them with a sleeping spell and the two are sent into the dream world where Dayu's past life is revealed to the Pink Samurai Ranger.

Dayu later finds the Furry Wart that was cast out by Master Xandred. She now has someone to talk to at last. Dayu tells the Furry Wart that Master Xandred had broken her harmonium and wants revenge for it.

Dayu thought Deker was dead. She went to the spot, where she thought he had perished, only to find his broken sword. There, she encountered Serrator once again. She was still mad at Serrator, after what he to her and Deker in the past. Serrator offered to fix her Harmonium, and locate Deker, if she agreed to serve him, which she did. She later finds Deker in the woods. Deker revealed to her that his Ultimate Duel didn't free him from his curse, due to his sword being broken. Dayu convinced him join Serrator, in exchange for fixing his sword, which he did.

Personality
Self-confident and arrogant, Dayu keeps mostly to herself, interacting with Octoroo and Xandred only when spoken to or during other needed times. She seems to have a rapport with Deker, though this is mostly due to him saving her life. After her shamisen is destroyed, she also displays a vengeful side, wanting payback against Xandred for destroying her signature item.

Equipment
Dayu's guitar, the "Harmonium" (transfigured into a shamisen) serves as her primary weapon, the headstock of the instrument conceals a short sword, with the headstock acting as its hilt.

Trivia

 * Dayu shares the same first name as her Sentai counterpart, Dayuu Usukawa.
 * A harmonium is not a stringed instrument, but a free-standing keyboard instrument, similar to that of a organ.
 * This could be a goof on Dayu's (or a writer's) part, or perhaps is just her nickname for her shamisen.