Roscoe was a birthday gift to Telesto from Astraeus, who adopted him as a puppy. Roscoe makes a happy addition to the household, as well as a loyal and therapeutic companion for Telesto. He calms them down when they're stressed and accompanies them during restless nights.

This dog loves people and play. Anyone that bats an eye at him will have Roscoe trotting their way for pettings. He also loves toys. It doesn't matter what kind they are. He'll grab a toy and plop it in someone's lap if he wants to play, or join another pet if they have something interesting. He also has a knack for learning tricks, which he can learn quickly when trained by Telesto. Roscoe can sit, stay, speak, roll over, and fetch/retrieve items by command. Among other things, Roscoe can be a bit of a crybaby. He'll whine at things that scare him or hide away from the source. He usually resorts to tucking himself between Telesto's feet.