The Scions were children artificially created using the Juniper Tree.
The Scions were made to look like similar to humans, with black hair, blue eyes and pale skin. In truth they were more like plants, being grown in pods and decaying into mulch when dead. They were stronger than humans and aged more slowly. Scions could control their own development and appearance, becoming more mature or dangerous with effort.
The Scions shared a group mind, allowing them to share emotions and feelings. This group mind could also extend to humans; they could read the minds of people and impress their thoughts on others. When angry, these psychic powers could be used to stun a human. The strongest Scion would be able to control the others. (PROSE: First Born)
In the 1980s, a seed of a Juniper Tree came to Earth and was found by the British Government. When they learned of its abilities, the Juniper Project was created to produce an army of soldiers. The first Scion, Sebastian, was a failure, being too peaceful. When they tried to train him for killing, Jack Harkness stepped in and stopped the project. The Juniper Tree was moved to Rawbone and the Scions were made into children for the inhabitants, who had been sterilised in an unrelated event. Most of the people of Rawbone disliked or mistrusted the Scions, but they eventually got used to them. In the meantime, a dangerous Sebastian was created, but Eloise avoided activating him.
In 2011, Gwen Cooper, Rhys Williams and Anwen Williams came to Rawbone while on the run. The appearance of a real human child disrupted Rawbone, turning people against the Scions. After Billy was nearly killed by his mother and Jenny stole Anwen to try to become a real adult, the leaders of the Juniper Project decided to kill the first Sebastian and activate the second. This new Sebastian took control of the other Scions, making them kill Sasha and then planned to kill everyone else in town. Before they could do so, Jenny stepped in and took control; her attempt to become an adult worked and allowed her command the other Scions. They confronted Sebastian and killed him, allowing them to return to their lives. (PROSE: First Born)