Natakus

Natakus are the failed attempts of combining youkai and god genetic material. The numbers of these failures continued to grow until Li Touten and his associates succeeded in creating a being that evolved enough to take human form. This final version became the War Prince, Nataku Taishi. All of these failures, these beasts, had gold eyes and were heretical beings like Goku.

Background
These creatures were made from the combined genetic material of Lower World Youkai and Heaven's gods, making them Heretics. As such, they all bare the mark of Heretics—Golden Eyes. Their creation was brought about by Li Touten, who aspired to take the throne of Heaven for himself. His attempts were to create a being that he could potentially use to gain political power in Heaven's higher ups; to make a being with almost unlimited power that would be forever faithful and obedient to him.

As the number of failures continued to pile up, Touten needed to do something with them. He started releasing them into the Lower World using the very gate his family had designed to make traveling to the Lower World easier. These released monsters helped quite nicely. They played as a distraction for the armies of Heaven to keep them from sniffing around. Touten and his followers continued to work towards creating their perfect weapon, a killing puppet. Eventually, they successfully created a being that had matured into a humanoid body. Touten presented this being, Nataku, as his son and he was given the title of war prince.

During Konzen, Goku, Kenren, and Tenpou's escape attempted to the lower world, they found Natakus' Monster room, a secret lab located right under the Emperor's nose—In the lower levels of his own palace. This was a storage room where the beast that were never released to the lower world were kept. Gamon, one of Touten's associates, was the keeper of theses beast and sicked them on Goku and the other. Gamon was killed by one of the very monsters he released. Kenren took up the role of decoy and stayed behind to take care of the beast while everyone else escaped.

After he'd thought he'd killed them all, Kenren found himself bloody and suffering from fatal wounds. Goujun, his superior, found him among the carnage having a smoke. He asked Kenren about these beasts and he more or less told Goujun that he and Tenpou had been suspecting something similar to what he saw before him from the start. Goujun told Kenren to surrender, and Kenren, never being one to let sleeping dogs lie, challenged Goujun instead, even in his state. He planned to go down fighting.

But it turns out that not all of the Natakus were dead. One was still alive. Kenren saved Goujun by pushing him down a shaft and told the beast that he felt pity for it and that it should eat him and make sure nothing of him was left. All the Nataku beast were suffering creatures. The beast killed Kenren and then ran amuck through the Jade Emperor's palace, destroying half of it. The creature was eventually killed by a group of Heaven's soldiers.

Trivia

 * The Nataku Beasts may be loosely based off the celestial monsters owned by Taoists, deites, and Bodhisattvas released in the Lower World as one of the 81 calamities Xuanzang and his group are meant to during upon their journey.