Athena was a blue-skinned mechanic who worked at Garage 10.
She met the Twelfth Doctor while he was visiting Garage 10 for spare parts for his TARDIS. She was visiting Garage 10 to get achieve her dream of becoming a mechanic. She brought to the Doctor's attention the fact that all of the garage's mechanics looked the same. They then found the person responsible and had him arrested by the Judoon. The Doctor offered her the position of travelling with him, but she refused so she could work at Garage 10. (COMIC: The Ministry of Time)