Stealthy and swift are the Deltas, a pack of dogs living in a place known as Maplehurst Marsh in some kind of odd marsh plant field. These dogs live in makeshift dens hidden within the fields and they are super stealthy, able to sneak up on a dog and ambush them without the targets knowing. The Deltas are cunning and crafty, very ingenious. They can hatch up great plans, and are the perfect dogs needed if you need any dogs to sneak up on someone, etc. Sometimes the Deltas are called "marsh runners" by non-Deltas and non-pack Strays.
They have the main pack color of green, and no one can ever see them approaching quite well. The Deltas are one of the "new" packs along with the Ghosts and Meteors, and this pack is open for a leadership role.