Chip

Early Life
Chip was a force-grown clone created by the Lady Cassandra O'Brien. He appeared to be almost Human but with distinctive markings across his skin. Cassandra claimed that she modelled him on her favourite pattern, a pattern she saw on the skin of the last man who ever told her she was beautiful. Chip began travelling with Cassandra and was onboard her ship on the day the Earth was destroyed in the year 5,000,000,000.

Following her apparent death he travelled aboard Platform One and rescued her brain connecting it to the skin taken from her back. Chip then travelled with Cassandra before finding the recently established colony of New Earth on which the Sisters of Plenitude were engaging in experimentation which was leading to the rapid development of medical treatment. He was able to hide Cassandra in an abandoned section of their hospital in the city of New New York and allowed her to rest there while he stole advanced medicines. His devotion occassionally irritated her. (DW: The End of the World, New Earth)

Encounter with the Doctor
When the Doctor and Rose arrived on New Earth he assisted in Cassandra's plans to kidnap Rose and use a psychograft to take control of her body. Despite the fact that she abandons him, to what she believes is a certain death at the hands of the human experiments who have been released, Chip was not able to stop worshipping his creator.

When the Doctor forced her to leave Rose he acted as a willing host even though the transfer of Cassandra's consciousness would inevitably put a strain on his hearts and lead to both of their deaths.

The Doctor then took Cassandra (in Chip's body) back to a party hosted by The Ambassador of Thrace. She told her younger self that she is 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. (DW: New Earth)