Agga was the king of Kish and the father of Ninani. He hated Ishtar for taking over his city, but feared her immense power, and therefore allowed her to do what she wanted.
When Agga discovered that Ninani was plotting against Ishtar with the Seventh Doctor, Enkidu and En-Gula, he had Ninani confined to her room and the rest imprisoned in the dungeons. He finally turned against Ishtar when she forced him to watch her enslave Ninani's mind, and he made an alliance with Gilgamesh. Although Ace saw this as a happy ending, the Doctor pointed out that Agga would force his daughter to marry Gilgamesh, who would later invade Kish anyway. (PROSE: Timewyrm: Genesys)