Cassopolis is a monolithic city which is a monument to technology and treachery. Boss Cass, the self elected president of Cassopolis, founded the city (more accurately city-state since it is specified to be a country) so he could have diplomatic immunity throughout Southern Rivers. Since then Cassopolis has become a safe haven for the worst Southern Rivers has to offer.
The city-state was first formed during Ty 2, though was inaccessible at that point. It was however, visible off the coast as a massive, towering city. It was mentioned Cass used it primarily to gain diplomatic immunity, thus making it harder for the heroes to fight and/or imprison him.
During Ty 3, the city was the only place in Southern Rivers to not be ravaged by the Quinkan, barring Ty's battle with the Dragonquin that did some damage to the skyline. The security of the city is likely due to Cass' advanced technology, its isolated location, and the fact he was allied with the Quinkan.
Upon visiting the city, it is clear many of the citizens (mostly Frills or other reptiles) share Cass' racist ideology towards warmbloods. Many also seem to have been brainwashed to view Ty as the enemy by default, hence their loyalty to Cass' cause. Several marsupials are also present in the city, including Ty's grandfather Tiberius and Mascot Mark, though they likely disagee with Cass' aims and are there for other reasons.
Inhabitants of Cassopolis in Ty 3:
- It is not specified how Cassopolis was created. It could have been an ordinary city Cass somehow took control of, or possibly a metropolis he formed from his armies of Frills, since Frills seem to be the primary inhabitants.
- Though Cass touts the city as great, it is oddly enough entered through a sewer pipe. It is very possible this is not the only entrance, however, at least prior to the Quinkan invasion.
- The only female Frill seen in the entire series is wandering about Cassopolis, though there are several copies of her.
- It is unknown how Cassopolis cannot be seen when it has an sewer pipe and the sewer pipe is very short and small and the city is very big.
- When you enter the pipe you could see monsters eyes through the bars.
- It is weird when you cannot see Cassopolis outside the pipe.
- Before you go to the pipe of Cassopolis it is night time.But when you go into Cassopolis it is dusk/sunset.It is probably unknown if the creators made an mistake.
- It is unknown how the citizens of Cassopolis get to their home.