Otringal is the primary island of Zeelich. The island is poking through the roof of the under-gas, and is divided into three main layers. On the Lower City is a training ground and a prison. The Middle City has a casino and a gift shop full of Twinsunian products. The Upper City, comprised for the elite, has the illustrious Imperial Hotel and the extravagent Palace of the Emperor himself. There is also an astroport and a harbour for off-world and on-world transportation, respectively.
Twinsen visits Otringal many times on his quest to save his planet. He is first brought there under the pretense that he is a wizard. When his true identity is revealed, he is being captured in the prison, which he manages to escape.
Later, after a daring escape from the Emerald Moon with Jerome Baldino, Twinsen crashes on Otringal. Among the quests he fullfills in the island are contacting the dissidents and obtaining the Sup fragment piece.