So how do the white walkers work?;
Do they increase their numbers when they win battles?
Can they attack fiefs?
Thanks for the help
This is just my observation, others might experience different.
White Walkers are just like the same as "Bandits", only stronger, slower, and larger party.
They don't increase their numbers at all. But if you defeated them, they will just respawn as a larger party beyond the Wall.
They are the same as Bandits, so no they don't attack fiefs.
Funny though, in my playthrough, a large army of White Walkers (around 450 troops) tried to follow and attacked a Caravan(50 troops). In so many attempts, the White Walkers keeps diminishing their numbers from 450 to 53 troops. They gave up in the end.