She becomes playable after completion of the first branching story mission (can be either one).
She shares the love her former self had for Zen, and strives to become stronger because of it.
She was created shortly after San's death and Zen's defeat at the bridge. Whenether she was thrown as well, jumped after Zen or materialized later is not known.
The Asuka ninja Zaji found both near a river in Utakata territory, and when trying to question the kunoichi he discovers that she is unable to remember anything except for Zen's name, so he takes them to the Asuka Village and gives the kunoichi a name: Kaede.
Predicting Zen's possible response at Kaede's existance he suggested the kunoichi remains hidden for a time, and she did while keeping an eye on Zen from the shadows.
When the Mara Mirror is revealed to be in possession of a merchant staying in Honcho Shimoyashiki Zen goes to find it, but arrives to find the merchant's corpse and no sight of the mirror. In her desire to aid him, she instructs him to chase the Mosu Ninja for the mirror, but avoids revealing herself. Hearing San's voice, Zen tries to reach out to her but as soon as he opens the door Kaede has already gone back into hiding.
It is after Zen fights Usuba for the mirror in Zengen Town that the two would meet. Nagi tries to attack an unaware Zen with a poisoned kunai but Kaede blocks the attack with her body to protect him. Zen is initially shocked to find San alive but Nagi soon reveals Kaede's true nature to him before fleeing. Kaede falls unconscious from the poison.
Back in the Asuka Village, Zaji explains to Zen that the kunai's poison was made from Hell Vine, and can kill Kaede if no antidote is made on time. The antidote requires Roadsturn Mushrooms, found in Anki Forest. Depending on the player's choice, either Zen or Zaji obtain the mushrooms and save Kaede's life.
Her identity revealed, she decides to try to aid Zen more actively, but the ninja remains indifferent to Kaede's efforts.
At one point the Yaksha Mirror is revealed to be hidden in Zengen Town, but at the same time Princess Sakuya has been kidnapped by the Kenobi Ninja. Kaede offers to rescue the princess herself but is rebutted by Zaji, who says that it's Zen's choice to make. If the player decides to rescue Sakuya then Kaede will try to reclaim the Yaksha Mirror, but arrive to find that Nagi already left with it.
Some time after this, after Zen's and Nagi's final confrontation, he returns to the Asuka Village but finds no trace of Zaji anywhere, Kaede explains that he has been kidnapped by either the Mosu or Kenobi, but at the same time the Ragoh Mirror has been revealed in Hachitenmangu and Shu is after it. Depending on the player's choice...
She displays the same abilities San had as a Fuka Ninja. She is fast, silent, stealthy, skilled in the usage on many tools and potions, and displays expertise in the arts of assassination.
In combat she uses elegant, dance-like combination of taijutsu and tantojutsu. For stealth kills she tends to favor stabbing enemies with her tantō, but has enough arm strength to be capable of breaking the neck of enemies with both hands.
And while her knife gives her shorter range and lower damage than Zen, she compensates with greater mobility, speed and jumping reach.
Cutscenes and concept art imply she still does not have complete mastery over her skills, and thus she rigurously trains to better herself. Despite this, she shows great potential by the implication that she was capable of defeating Usuba and Uzumushi by herself.
"Love...? I don't know... I just want to be with Zen. I want Zen to... to smile at me"At first glance, Kaede is an emotionless individual. She only talks when needed and does not express her opinions. This does not mean she actually is emotionless, as some cutscenes and dialogue demonstrates this behavior is mostly because she herself doesn't undestand her feelings or how to express them.
Her actions are derived from her love towards Zen and her desire to make him happy and be accepted in return. While his harsh treatment saddens her, she still keeps her devotion.
In any other circumstances she remains calm, cool-headed and somewhat timid. The only thing that seems to upset her is whenever she fails a mission on Zen's behalf, or when his wellbeing is at risk.
Ultimately, she is not San but her own person. This is the main reason for Zen's distrust, and the overall message Zaji tries to convey to both her and Zen.
Kaede loves Zen and dedicates her life to him. Initially he is cold, harsh and somewhat cruel to her presence, as Kaede is a shadow of his dead love and not the real San, but while his behavior hurts her, it doesn't deter from her efforts. If the "Two Flowers" story path is taken, Zen eventually warms up to her and together they leave to hide the Tenma Mirrors again. Zaji's words imply that they might eventually find happiness together.
If the "Reflections" story path is taken, Zen never grows to care for Kaede and eventually kills her in his obsession to recover San. In the "One Flower" story path, Zen appears to remain indifferent, but it's slightly implied by Zaji that he's more miserable because of her death.
Zaji found both Kaede and Zen in a river in Utakata and brought them to the Asuka Village. Continuosly through the game Zaji demonstrates a caring side towards Kaede, giving her a name when she didn't have one, giving her advice, helping her better her skills as a ninja, asking Zen to obtain the Roadsturn Mushrooms to save her life and doing it himself if Zen refuses. In general he takes something of a mentor role towards the kunoichi.
Shu was her original self's murderer, and he shows some disdain towards Kaede's existance, claiming she could never take San's place in her beloved's heart and that her presence will only bring him sorrow, before attempting to kill her. However, his dying words imply he sees in Kaede's devotion to Zen a powerful love, the kind he himself desired.
- She is a reflection of San in the literal sense as well. All the details in San's heavily asymmetrical design are turned in the opposite direction for Kaede.
- Like San, she has heterochromia. Her left eye is colored aqua green.
- Japanese maple leaves are a symbol of determination, change and patience. All of these qualities are displayed by Kaede and her backstory.
- Kaede's name may have been derived from the maple leaves tatoo in her left leg.