William is a Golden Retriever puppy and the de facto leader of the Royal Guards. He's responsible, loyal, practical, intelligent, courageous, elegant, and well-mannered. He gets along well with and would do anything for his fellow Royal Guards and the citizens of Pocket Kingdom. He has a younger twin brother named Willis, a sister named Angela, and is in love with Stacy.
After "The Homecoming"
William is overjoyed to have Ava back and thus redoubles his efforts as a Royal Guard. After he starts courting Her Majesty though, he is a little dismayed to find that he has less time to focus on his duties. However, he broke up with Ava after realizing Ava must marry a cat from aristocratic blood and that they can't have offspring together due to them being different species.
- Queen Ava V
William and Ava courted for a time, but that changed when Stacy moved to Pocketville. She and William fell in love at first sight, and Ava, wanting them to be happy, broke it off with William and wished them the best.
William: "Pocketville: Rise of the Blood Moon" Version
- Like the rest of the royal guards, he is a Senior Royal Guard.