A vassal nation is a nation that has chosen to be subordinate to another nation, called the overlord nation. Vassals receive protection and bonus claims from their overlord nation, but sacrifice some of their independence in return.
To become a vassal nation, a nation's Leader or Coleader may request another nation to become its overlord by using /vassals pledge (name of overlord nation). The other nation's Leader or Coleaders must be online in order to accept the request by typing /accept or deny it by typing /deny.
The overlord and its vassals can communicate through the vassal chat channel, using the command /vc (message). Messages in this channel will be shared between the overlord and all of its vassals.
Note: Subjugation is currently disabled.
If a nation occupies all the towns of another nation, they can force it to become their vassal through subjugation. The nation leader or co-leaders can perform this by typing /subjugate <name of fully occupied nation>.
A nation cannot be subjugated if:
Vassal nations cannot form or break alliances, nor can they add or remove enemies. They are permanent allies of their overlord nation, and their relations with other nations will always be identical to their overlord nation's relations. However, this means that nobody can declare a vassal nation as an enemy directly - they must enemy its overlord instead. If the overlord is powerful, this can deter nations from attacking the vassal.
Vassal nations inherit the nation claim bonus of their overlord, and vice versa. For vassals, the nation bonus received from the overlord depends on how much of the vassal is occupied. For example, if 40% of the vassal's towns are occupied, it will only receive 40% of the nation bonus of its overlord.
The overlord nation has several powers over their vassals.
The overlord nation's Leader/Coleader can rename a vassal using /vassals rename <name of vassal> <new name>. Vassals cannot change their names themselves.
The overlord nation's Leader/Coleader can set a daily tax on a vassal by using /vassals settax (vassal name) (percentage).
Vassal tax controls how much of the town bank of towns in the vassal nation will be transferred to the overlord nation's bank, at the start of each Towny day. For example, if a vassal's town has $10,000 in its town bank, and its vassal tax is set to 1%, then the town will pay $100 to the overlord nation.
The maximum vassal tax rate is 2.5%.
A vassalage relationship can be terminated in four ways.
/vassals release <vassal nation>./vassalrevolt./vassals terminate.
Declaring a vassal revolt through /vassalrevolt will forcibly release a vassal from vassalage. However, all of its towns will lose siege immunity and its unoccupied towns will become occupied by its former overlord. This is intended for subjugated vassals, as they cannot use /vassals terminate.
If the vassal was subjugated, they can only revolt 10 days after being subjugated. The time remaining until such a vassal can revolt is shown in their /n information screen.
After revolting, your former overlord will be unable to subjugate your nation for 96 hours (4 days). During this period, you must begin a revolt or liberation siege to free your towns. Otherwise your former overlord will be able to subjugate and re-vassalize you.