The Rarkelians were a species known for being peace-loving and being dedicated to ecology, culture and spreading inclusive ideas of harmony. The Eighth Doctor mentioned having visited Rarkelia and was present when humans first encountered them, "way beyond" the 60th century.
However, history was changed and the Rarkelians were enslaved by the Earth in the 41st century, being able to offer little resistance due to their peace-loving ways. A number of Rarkelians, including Bourakai's brood, were slaughtered and he himself had to escape from a prison camp. He and Teeja travelled back in time to 2020 using stolen chrono-warp engines to kill the Doctor and avert the timeline. (AUDIO: Divine Intervention)