Chip

Chip was a force-grown clone created by the Lady Cassandra O'Brien to serve her. He appeared to be almost human but with distinctive markings on his skin.

Creation
Cassandra claimed that she had modelled him on her favourite pattern, a pattern she had seen on the skin of the last man who ever told her she was beautiful. Chip travelled with Cassandra and was onboard her ship on the day the Earth was destroyed in the year 5,000,000,000. (TV: New Earth)

On New Earth
Following Cassandra's apparent death, (TV: The End of the World) he went onto Platform One and rescued her brain as well her "pretty blue eyes" which were salvaged from the bin, connecting it to the skin taken from her back. Chip travelled with Cassandra before finding the recently established colony of New Earth. There, the Sisters of Plenitude were engaging in experimentation leading to the rapid development of medical treatment. Chip hid Cassandra in an abandoned section of their hospital in the city of New New York. Cassandra rested there while he stole advanced medicines and moisturised her skin. His devotion occasionally irritated her. He had an Irish accent. He was referred to by Cassandra as a "walking doodle" when she entered his body before dying.

When the Tenth Doctor and Rose arrived on New Earth, Chip assisted in Cassandra's plans to kidnap Rose and use a psychograft to take control of her body. Though he complimented his mistress's restored youth, he was saddened to see her old skin and brain had expired during the transfer. Once Cassandra learned of the Doctor's presence inside the hospital, Chip advised her to imitate Rose's "Old Earth Cockney" accent and provided her with a narcotic perfume which she would later use to knock the Doctor unconscious.

On Cassandra's orders, Chip released the human experiments from the hospital's intensive care unit when her attempt to blackmail the Sisterhood failed, and fled with her and the Doctor down to the basement. Despite the fact that she abandoned him to what she believed was a certain death at the hands of the infected, Chip continued to worship his creator. He survived the crisis by jumping down a waste chute and hiding in one of the containment pods in Intensive Care.

When the Doctor forced Cassandra to leave Rose, Chip acted as a willing host for his mistress. However, the trauma of the day's events, coupled with the transfer of Cassandra's consciousness, strained his heart and led to both of their deaths. (TV: New Earth)

Death
The Tenth Doctor took Cassandra (in Chip's body) back to a party hosted by the Ambassador of Thrace. She told her younger self that she was beautiful before dying in her own arms. This incident created a predestination paradox that would eventually lead to Chip's own creation in his current form. (TV: New Earth)