Dunno when it ends.
Classic and Casual are different.
Classic
High performance world in an "old" jacket. The current settings are a bit of a throwback to the past. Don't let that fool you though, it's a rather competitive setting at a substantially higher speed than a regular world (nowhere near a speed round though). This does indeed have an end phase at some point.
Cassual
Servers dedicated to accustom those who aren't able to play on the regular worlds due to time constraints or other reasons. Starting there is usually done through transferring a mirror of your original starting village you had on the regular world. This village can never be captured from you, however it can be attacked (not sure if demolished). These worlds do not usually have an end phase.
