Angus

Angus is one of Roofus' sons. He can be found in World Quack Centre.

How to Rescue in Fur Fighters
Opposite the security room is a door leading outside. Hidden next to a tree is a mound which Roofus can dig through. After digging through a couple more mounds he will reach Angus.

How to Rescue in Fur Fighters: Viggo's Revenge
After taking the normal elevator, General Bristol will point to him on the other tower. To get him, push the buttons in the center of the area back and forth. Eventually, Angus will hop over and wait for his father near the telescope.

Trivia

 * For whatever reason, his location is swapped with Fulton in Fur Fighters: Viggo's Revenge.
 * In addition, after the cutscene of Angus moving to where you are ends, if players move fast enough to the side of the tower with the telescope they can see the spot he used to sit on moving back to the other tower.