Baal D'jo

 was a scientist and a Silurian/Sea Devil hybrid. He was the son of Auggi and Daurrix, and the brother of Sula and Tahni.

Despite hybrid eggs normally being destroyed due to being against the Silurians' sacred views of eugenics, Baal, Sula and Tahni's eggs were not, and their parents were not executed because of an imminent cataclysm was predicted. However, they had a shortened lifespan and were sterile, and sought to find a way to cure this condition after awakening from hibernation many millions of years later. To do this, they kidnapped a human teenager, Marc Marshall, and experimented on him, intending to use his DNA to cure their condition. After Baal made an agreement with the Third Doctor to have Marc returned to the mainland, he and Sula sought to treat their condition through more ethical means with the help of Dr Liz Shaw. After Auggi's Silurian fleet failed to invade the British mainland, Baal and Tahni took command of the Silurian shelter. Liz offered to continue working with the hybrids. (PROSE: The Scales of Injustice)