There will be ronins for hire, and the amount of them will increase over time as more and more landed characters lose their holdings. Before becoming a ronin, a landless character will (for a time) be able to "wander around" looking for new land.
is there a claim system in this game? or is it "might is right" that determines who holds what?
But you can play as a ronin if you has been defeated?
Hmmm.... sort of a GiE-type mechanic?
Government in exile... only other example of a playable landless entity I can think of.