I am far more familar with tabletop RP in real life and Roll20.

In these settings, which seems similar to the above, your create a character for that story, and you are collaborating in writing that story. 

If you remove yourself from that story due to inactivity or similar, it is left to the others to resolve that issue.
Typically the character is written out, such as going to the town, and them deciding they got other buisness elsewhere. Sometimes if the character has been very important, they might turn into an NPC or Cameo role by the GM with a limited role. Usually this is a tribute/honour for this to happen.

In games where there are pre-generated characters, these may end up getting continued. I imagine in this format, this happens significantly less than in Tabletop RP given that there is a lot more creative control.