The Nu-Humans were genetically engineered humans.
They were purple humanoids and as big as silverback gorillas. Nu-Humans had very long arms and had yellow eyes.
The humans wanted to get the minerals from the planet Hope Eternal. However, terraforming would destroy the minerals that the humans wanted to mine. That's why Claudia Manson wanted the humans to adapt to the planet. He modified the human bodies to suit the alien environment. He completely reworked the humans. They had new DNA sequences and new organs.
The first Nu-Human that was born was a monster. It suffered complete organ failure. The next few Nu-Humans were the same so Claudia Mason's grandfather experimented using alien DNA which he mixed with the human DNA. It seemed to work.
From then on the creatures called themselves Nu-Humans and moved to Hope Eternal. However, it did not work like Claudia Mason's grandfather had expected. In the second generation of Nu-Humans, the alien DNA caused diseases and mental deterioration. Some of the Nu-Humans became murderous.
When Claudia died, Trevor became the new governor of Hope Eternal. He told the Nu-Humans what his relatives had done to them. Then the Eleventh Doctor gave him some of Rory's DNA, so that Trevor could use it to heal the diseases of the Nu-Humans. (AUDIO: The Nu-Humans)