|Season:||Android Kikaider (Manga)|
|Number of Episode|
Full list of appearances
Rieko appears as a young woman with dark hair in a ponytail and is usually seen in a dress. In her android form, she has a short 'hairstyle' with a body featuring concentric circles on the chest area.
Rieko is friendly and compassionate, striving to protect Akira and Rumi from Professor Gill and SHADOW for use in their evil plans. She grew rather close to the Kikaider Brothers especially Jiro for his compassionate side and scolds any sign of distrust between them especially when Ichiro arrogantly said he didn't need Jiro, which caused him to leave for a while.
Rieko is an advanced android with a thought process close to a human, showing higher functions like feelings and defying a command at one time. In either her normal or android form, she is able to shoot beams out of her breast area to attack enemies.
The Kikaider Brothers encounter Rieko running from the Hakaider Squad with Akira. They offer assistance while fighting off the Hakaider Squad with Ichiro taking Rieko with him while encountering robots from SHADOW. After losing both parties, the brothers ask for Rieko's identity who reveals Akira as Professor Gill's son and holding the plans for his super weapon Giant Devil. Rieko and Akira are brought to the Komyoji House for protection while watching to Komyoji family leave for Europe with the Kikaider Brothers.
With Rieko putting Akira asleep after washing him, she speaks with Jiro and expresses how she appreciates Jiro's kindness. When a SHADOW robot abducts Akira and the brothers try to fight off with Jiro flying away, a spy robot tricked Ichiro with Jiro's voice scolding him. When Rieko and Jiro tried to explain it to Jiro, he didn't believe them and exclaimed that he'll go find Akira with Rieko without Jiro. Jiro obliges and leaves the house in the night. Rieko scoled Ichiro for this, but he said he'll be fine on his own.
On a beach near the SHADOW base, they encounter SHADOW robots as well as Hakaider who helps destroy them. Hakaider asks for an alliance while holding his other child Rumi. Reluctantly they agree and go back to the Komyoji house where Jiro and a new android called Rei were at. As Rieko tucked in Rumi, Hakaider comes in and reveals Rieko to be an android he created to look after his children and his intentions of using Rieko as a tool to drive a wedge between the Hakaider brothers while keeping her identity a secret. With a spy robot in sight, Rieko disobeyed orders and destroyed it.
Later, the house was attacked by more SHADOW robots looking for Rumi. As the Kikaider Brothers and Hakaider fought against them and Zadam, Rieko had to run from a tentacled robot that managed to grasp Rumi until Rieko assumed her android form to fight. However, reinforcements showed up and Rieko sacrificed herself to save Rumi. Jiro mourns her death and makes Rieko a grave.