Radic found Fauntleroy at a Pokémon Breeder's in Goldenrod. The Breeders specialized in purebred Houndours, and as a result of years of inbreeding, several of the recent puppies were born with a form of hip dysplasia. Eager to get the puppies off their hands, they willingly let Radic take one. Fauntleroy was named after the Founder of that particular Breeding center.

Since Radic got him when he was fairly young, Fauntleroy is very attached to him. As a result of his upbringing with the Breeders, he has a fairly refined, distant air about him most of the time, and speaks very carefully. He very rarely indulges in any nonsense from his teammates, particularly Poe or Chopan, and is calm, although somewhat aloof. While rambunctious as a puppy, when he grew up he became very controlled and calm.

This is in part because Fauntleroy has that variant of hip dysplasia, and it hurts him to move too strenuously or too often. Since most Pokémon with that sort of defect are released or stored in a PC Box, never to be seen again, the operations required to help are extremely expensive and only performed by a few experts. Radic doesn't have the money to help his Houndoom, although he's trying to save up to give him the operation, and he hasn't even found a Pokémon Center yet that has a doctor he can trust to do it.

In the meantime, Radic uses Potions to ease Fauntleroy's pains when he comes into battle. His hips have just gotten more painful as time's gone on, and now Fauntleroy barely walks at all, often lying down when sent into battle. He prefers to spend his time curled up by Radic's feet, sleeping, or generally not moving around very much.

Fauntleroy can be cold and standoffish to people he thinks are beneath him, which are most other Pokémon. While not as much of a raging egomaniac as Ruby, he still tends to treat others in much the same way. It's easy to get on Fauntleroy's bad side, and not so easy to leave it. He can hold grudges for a long time, although he'll take his time in getting revenge. After all, one has to be sophisticated about such things.

Fauntleroy gets along alright with Dipsy, although he thinks he's not as smart as he says he is, and tolerates Chirin and Rezna. Since he was found so late, he doesn't have very strong attachments to the rest of his teammates, but he's very very loyal to Radic. If out and about, he'll growl and bark to protect him from any strangers or foreign Pokémon.

Unlike the rest of Radic's Johto Pokémon, Fauntleroy looks like a perfect Houndoom thanks to his breeding. Unfortunately, his hip disorder makes it difficult for him to move, making contests impossible, and battles very awkward. Not that anything like that has ever stopped Radic from raising a Pokémon before though. Radic generally keeps a lot of Potions and Super Potions on him just in case of a battle... if he rubs it on Fauntleroy's legs, he can stand up long enough to fight.

In Johto, Fauntleroy had Flame Thrower, Crunch, Roar, and Faint Attack.

Fauntleroy is in fics where Radic's later Pokémon come into play, mostly Together Forever.