But that is not the only thing that have made them move.
It was also the fact that the person who was attacking the tavern is an outsider.
The factions here might have great rivalry with each other, but they also know to guard their interest.
There is a reason why these factions did not destroy the other factions but only stopped at rivalry. They do not want a war with each other and the other one is to monopolize this island city.
If Hanging Head is destroyed or even any other factions that have stabilized here were to be destroyed, then all of their efforts would go down the drain and outside influence would come it.
They already created a stable ecosystem here to feed each other and benefit each other. How could they let an outsider changes these things?
So, all of the factions and forces all over the city had now come to defend the Hanging head tavern and threw out the invaders.