Last Son of the Nocktress

The last son of the Nocktress is the main antagonist of the Finnish-Chinese co-produced movie Jade Warrior that combines elements from Finnish Kalevala mythology with the wuxia genre.

He was portrayed by Taiseng Cheng in his demon form and by Markku Peltola as Olavi Berg.

Ancient China
At the dawn of time, the eldest daughter of Hell, the Nocktress, birthed nine sons. Eight of them came to the world and were named as Fear, Pain, Madness, Ugliness, Lust, Hate, Greed and Blindness. The last son was left unnamed and stayed hidden from the world. Aspiring to bring hell upon earth, he waited for Seng-Pu the Smith to create the Sampo, a machine that can be used as a gate to hell.

Once the Sampo was created, the demon stole it from humans. Much to his disappointment, however, he discovered that the smith had crafted the Sampo so that only his son can activate it. Said son, Sintai Seng-Pu, is set to slay the last son of the Nocktress with the reward of liberation from the cycle of reincarnation. The demon was forced to wait for the warrior for a century.

In China before the time of the first known dynasties (2000 B.C.), the half-Chinese and half-Finnish Master Sintai Seng-Pu has been trained by monks to battle the last son of the Nocktress. Traveling toward the swamps of Barun Urta where the demon is with the Sampo, he's escorted by an army of monks who have left their temple empty to ensure that the warrior won't deviate. When they're close to their destination, they pass the home village of Sintai's armour-bearer and friend Cho. Anticipating that he'll likely die in his fight against the demon, Sintai sneaks to the village while Cho impersonates as him. Wanting to experience one day as an ordinary man before letting go of earthly pleasures, he intends to catch up with the army before they reach the swamp. Unfortunately, his stay in the village stretches out due to his crush on the village elder's granddaughter Pin Yu. Without anyone's knowledge, the last son of the Nocktress spies on Sintai through a fly walking on the face of a female villager.

By the time the army of monks reaches the swamp, Cho rides off to fetch Sintai, unable to keep up the charade. The last son of the Nocktress slaughters the entire army off-screen. Sintai arrives afterwards, finding the demon waiting on the Sampo. The demon tries to convince Sintai to work with him to open the Sampo. He manages to instill doubt in Sintai's mind by claiming that Pin Yu won't wait for him. Sintai decapitates the demon without killing him and returns to the village with the talking head. There they overhear the conversation between the long-lost lovers Pin Yu and Cho who rekindle their love after years of believing each other dead. The demon tries once again to convince Sintai to work with him, but the disheartened warrior decides to try his luck with Pin Yu in a following life. To prevent the demon from dying, he seals the head in a metal box that was crafted by his father to open only upon Sintai's touch. Sending his wolf friend to take the box north to prevent anyone from finding it, Sintai commits suicide. Cho and Pin Yu chase the wolf to East Karelia and stay there to guard the box which is buried with them.

Modern-day Finland
Several millennia later, the metal box containing the last son of the Nocktress is discovered in the hands of Cho's bog body. It's studied by a Kalevala researcher Olavi Berg who accidentally discovers that it reacts to the organic powder made from the hair and nails of Kai Pelkonen, a down-on-his luck novice blacksmith who's Sintai's reincarnation. Berg manages to use the powder to get the box partially open for a moment. The demon inside uses the chance to telepathically still the suicidal thoughts of Kai whose girlfriend Ronja, Pin Yu's reincarnation, is moving away. He also causes Ronja's car to malfunction, forcing her to stay.

Eventually Berg visits Kai's secluded home in the outskirts of Helsinki, bringing the box with him. Kai opens the box by touching it, and as Berg lifts the lid, the last son of the Nocktress inhabits his body, killing the real Berg. From this point on, Kai begins to get glimpses from his past life as Sintai Seng-Pu. Speaking cryptically about their shared history, the demon promises Kai that he'll get Ronja back if he forges the Sampo. As Kai uses the metal from the box to try and forge the Sampo, the demon prepares organic powder from his nails while hindering Ronja's departure further.

Through several stages of failure, Kai manages to forge the Sampo in his basement. The demon discreetly makes it his own through his organic powder. Kai opens the Sampo, bringing hell to earth. A green whirlwind appears in the sky above the Sampo, and everyone else but Kai and Ronja are mesmerized to stare at it. Having fallen unconscious and taken away by Ronja, Kai returns to his basement to confront the demon. They engage in a duel by using martial arts and hammers. The demon gets the upper hand, but Kai remembers a move created by Pin Yu and Cho, the Strike of Concealed Happiness. Using it to take the demon by surprise, he pushes his opponent to be impaled by one of the blades adorning the Sampo. The demon then tries to pull Kai into the blade as well, but he's protected by Pin Yu's amulet that Ronja gave him. As Kai declares that they're done, the demon dies in Berg's body with sadness while the Sampo's effect vanishes.

Powers and abilities
The last son of the Nocktress is a powerful demon with various abilities. He's shown to be capable of telepathy, using a fly to spy on distant events and extending his influencing to the faraway happenings, like he does to prevent Ronja from leaving Helsinki. While in his full power in China, he destroys an entire army of warrior monks. He survives a decapitation and is able to live as a bodiless head for millennia inside Seng-Pu the Smith's metal box. After he takes over Berg's body, he shows himself to be a skilled martial artist with paranormal strength. He can speak Chinese as well as Finnish.