Boney is the pet dog that belongs to Lucas, Claus, Hinawa and Flint. Boney is their only pet to appear in the game. He has been with the family for many years, which is shown by how the sprites grow.
In Chapter 1, Night of the Funeral, Flint takes Boney with him into the forest after the fire is put out. He hopes that Boney can sniff out his wife, Hinawa, and his twin children, Lucas and Claus. Later, he runs through the forest and back to Tazmily to get Duster from the house.
Boney does not have the ability to obtain or use any PSI abilities. He can sniff out an enemies weakness, but it does not work all the time. The only fighting ability he has is biting. He can equip hats and collars only. He can also hold onto items another member or Lucas' party cannot.
From there, Boney will accompany Lucas and the rest of his team until the end of the game.