|“||I finally took over. At first the girl within this body resisted, and I wasn't able to take control. But then Shyamalan weakened her, and she wasn't able to resist anymore. When I no longer needed his assistance, I killed him. Those who summon me always die by my hands. Why would these seemingly intelligent lifeforms wish death upon others? I find them all painfully foolish. So I destroyed them one by one, eating away at the arrogance in their spirits. I have one desire. To bring peace and quiet to this chaotic universe... because I long for silence.||„|
|~ Ryunka taking over Sayaka's body|
The Ryunka is a sentient weapon which served as the bigger bad in the first season of the anime series, Birdy The Mighty: Decode. She is also the indirect cause of the events of the serial murders committed by Nataru Shinmyou.
Having destroyed several planets in the past, the Ryunka was brought to Earth by a group of alien criminals, who attempted to awaken it while under the employ of psychotic businessman Satyajit Shyamalan. After Geeva, one of Shyamalan's alien operatives, was stopped by Birdy, Shyamalan's operatives began transporting the Ryunka, only to engage in a car crash with a vehicle containing Nakasugi heiress Sayaka Nakasugi. The wreckage was discovered by a mysterious girl who implanted the Ryunka's consciousness into Nakasugi, which rapidly healed her injuries.
Over the course of the series, the Ryunka began gradually taking control of Sayaka's body, causing her to go on murder sprees while she was unconscious, and at one point destroy an entire town full of people. The Ryunka also massively changed Sayaka's personality, emboldening her and giving her far greater levels of confidence and energy.
After Shyamalan murdered Nakasugi's grandfather, the mental instability triggered caused the Ryunka to regain just enough control of her body to force her to kill her maid, Yoshie. A traumatised Sayaka considered Tsumotu's offer to run away with her, only to change her mind at the last minute and go with Shyamalan on a "retreat" aboard his ship the Lost Bird. Shyamalan then drugged her and hooked her up to a machine called the Ajivan System, which sufficiently weakened her to the point of giving the Ryunka full control over Sayaka's body. The Ryunka began killing all of the birds in the sky around the Lost Bird, before killing Shyamalan, and extending her reach into the nearby ships, and then extending it further, crystallising the bodies of millions of innocent people in the city just offshore, as well as triggering explosions throughout the city.When Tsutomu tried to save Sayaka from the Ryunka, the Ryunka simply mocked him, saying that she (the Ryunka) simply is Sayaka, and that the two had become inseparably one, and that all of this was Tsumotu's fault for giving Sayaka to Shamalan, before expositing on her motives to create "peace" and "silence" throughout the universe because she hated how noisy it was. Meanwhile, Birdy pulled the Ryunka's external expression underwater, and came to the Lost Bird in order to kill Sayaka and destroy the Ryunka for good. As The Ryunka continued to converse with Tsutomu, Sayaka's personality began conflicing with the Ryunka's, and trying to resist its' control. Sayaka pleaded with Tsutomu to help her, but The Ryunka continued to wrestle back control. The Ryunka then released a massive energy blast, before transforming into its true form, a giant four-legged monster, and tried to kill Birdy using repeated energy blasts. Eventually Tsutomu managed to get through to Sayaka, giving her brief control of her new form, which she used to turn it into water. Sayaka was left on the floor, confused and unsure of what was going on. The Ryunka then re-took control of Sayaka's body, and told Tsumotu to give up, since Sayaka belonged to her now. The Ryunka then used Sayaka's memories to pretend to be Sayaka, and made Tsutomu promise to never leave her side, before once again mocking Tsutomu by saing "You can stand by and watch as I kill every living being on this planet." Tsutomu then kissed Sayaka, and in so doing he pulled the Ryunka into his own body, then pleaded with Birdy to kill hiim so that the Ryunka couldn't gain control. Birdy then regretfully punched an energy blast into Tsutomu, killing him and freeing his body of the Ryunka parasite, which Nechla then captured in a cage and took back to be imprisoned on her home world. The girl who iimplanted the Ryunka into Sayaka then tried to barter with Nechla to have the weapon back, but Nechla told her that no amount of money could convince her to give away such a deadly weapon, then promised to see the girl in court.
After being freed from The Ryunka's control, Sayaka lost all of her memories from the time it was in her body, and forgot having even known Tsutomu, let alone having loved him.