Cestulus is the sole inhabited planet in the Davien system, and one of the main centres for trade with the Banu. It was terraformed in the early 26th century. Due to a thin atmosphere, the majority of human habitation is underground.
Jata is the Cestulan capital. Built underground, it is the location of Aegis Dynamics' corporate headquarters. It has a unique 'open air' underground cityscape.
New Arden is famous for holding the largest Travellers' Day Gathering within the UEE.
Cestulus has a long history of political activism. In 2529, military intervention was required to halt a two week long riot in Jata over the introduction of the UEC as a unified currency. In 2545, terrorist bombings collapsed several biodomes, and indirectly led to Ivar Messer becoming Prime Citizen. Even today, Cestulus remains a hotbed of radical politics.