The Rook is a really interesting element to the game, and while I know that it is being fleshed out, I figured that I would share my ideas on how The Rook could bring more life to the world of Glitch.
The Rook is the Adversary, from my understanding. While the Giants may have particular interests and rivalries, They are all a force of creation in the world, whereas The Rook is a force of entropy. I would use that as an incentive to keep players active in the world, even in the areas where they don't normally go.
If the resources in an area are not tended for a certain amount of time, they start to decay. Meaning without watering, the trees die; without petting, pigs get sad and sick; without massages, butterflies whither; and without mining rocks crumble to useless husks. If this continues long enough, the area could take on a sickly appearance, and become Rook Blighted, where it starts having an effect on Glitches. In these areas, skills and actions have a much lower chance of working, (though the Glitch could still get some XP and possibly mood), mood atrophies at a higher rate, and even energy is sapped (though I wouldn't make it as harsh as the Winderlands). So, while you might water and pet the trees, they wouldn't get much nourishment from it, and you would have to work together to repair the damage. This could also be extended to include other skills like Cooking and the like, where you have a lower chance of success, but if you do succeed, you work toward healing the Blight. Rook attacks would be much more common in Blighted areas. This could also be a way to expand the Street Projects more, as once a street is cleared of Blight it could be restored thought a Street Restoration Project, while would be similar to the existing Street Projects.
To make this even more damaging, the infection should spread to connecting streets over time. Basically, it will just decay the resources on the connecting streets at a higher rate until they are no longer Blighted. The fewer Glitches that visit a street, the faster Blight takes effect. This encourages people to explore, and makes the wilderness potentially more menacing, but it also would encourage Glitches to interact with their environment more.
To make things more interesting, and to keep the pressure of the Blight from just being on the edges of the map, random Rook attacks could happen at any location, and cause a rapid decay to the Blighted state. This would make defending against the Rooks even more important, since the Blight could affect surrounding streets. I would bias the random Rook attacks on areas that are populated the most. Basically, the way I see it is that The Rook is both the cause and effect of Entropy. If an area decays, it will bring The Rook, but The Rook is always coveting the Giants' works, and looking to destroy them at their most precious places.