In 994, Castle Wyvern sheltered some peasant refugees being chased by Hakon and his Vikings. When a few gargoyles were playing with Bronx, a small fight broke out between the young gargoyles and the peasants. Goliath sent the gargoyles and the beast down to the rookery as a punishment. Fortunately for the group, this punishment proved to save their lives. During the day, the Vikings sacked the castle and smashed all the sleeping gargoyles. Bronx, along with the other surviving members of the clan, went to avenge their slain clan-mates and was cursed to sleep until "the castle rose above the clouds".
One thousand years later, David Xanatos purchased Castle Wyvern, and topped his skyscraper with the castle, thus breaking the spell. Like his fellow clan-mates, Bronx was named after a New York place-name: the Bronx.
Bronx accompanied Goliath and Elisa to Avalon, and from there, accompanied the two and Angela during the “Avalon World Tour”. When the Avalon Travelers stopped in Ireland, Bronx encountered Rory Dugan, and helped lead him to his true destiny as the reincarnated Cu Chullain. While visiting Guatemala, Bronx briefly borrowed Obsidiana's magical pendant, allowing him to remain flesh during the day. He was alongside Goliath and Angela when they were captured by Nokkar.
Bronx, alongside the remaining members of the Manhattan clan, was nearly killed by the Hunters' missile strike on the Clock tower, but he narrowly escaped, carried off by his clan-mates. When David Xanatos offered the clan use of Castle Wyvern, Bronx took the opportunity to bond with Alexander Fox Xanatos. 
While the Manhattan clan celebrated Halloween, Hudson took Bronx to visit Jeffrey Robbins, where Bronx and Gilly slept comfortably in front of the fire. The two returned to the castle to discover Thailog had crashed the Xanatos Halloween Masque. Bronx was injured by Thailog, who fought the clan to secretly obtain DNA samples.
When Brooklyn returned from his journey through the time stream, Bronx was curious about the new gargoyle beast, Fu-Dog. The two sniffed each other before being called off to battle the Pack in Times Square.
Bronx's name was bestowed upon him by Brooklyn in 1994, after the Bronx in New York (presumably because it sounded close enough to an animal's bark or growl).
Although a member of the Manhattan Clan, he is not technically a gargoyle. Rather, he is a gargoyle beast- resembling a dog more than a human. Physically, he bears a mastiff-like build about the size of a young calf and has two conical lower molars with severe underbite. He could not talk, but was nevertheless depicted as intelligent and a fully-fledged member of the clan. Bronx is often found sleeping by Hudson's recliner, but occasionally in other places - such as on Lexington's magazines while Lexington is trying to read them. Bronx is a fierce and formidable fighter when there is an emergency, a loyal friend, and a very good judge of character.
Like all other male gargates, Bronx’ eyes glow white when he is enraged, and he possesses formidable strength. As with all gargoyle beasts, Bronx lacks wings, but still turns to stone during the day.
He accompanied Elisa and Goliath to Avalon and the quests that Avalon sent them on. On Avalon, he met his future mate Boudicca, another gargoyle beast that is part of the Avalon clan. In the episode Hound of Ulster, Bronx was mistaken for the eponymous hound by the reincarnation of the Irish Hero Cu Chullain and his nemesis the Banshee. Cúchulainn comments that he once had a dog like Bronx, suggesting that within the Gargoyles universe, a gargoyle beast served as partial inspiration for the legend.
Bronx's biological parents are "Chomp" and "Chaw". He has a deep blue color, fan-shaped ears, two small horns above his brows, and three spikes running along his back. His tail is very short.
Bronx hates pigeons, with an almost savage fury.
- Earlier in the development of the series, Bronx was slated to be the comic relief character. He was described as "angst-ridden", the one member of the clan who really wasn't happy about being awake in the modern world. Concept drawings suggest Bronx being able to hover just a few inches above the ground by flapping slightly oversized ears like a hummingbird. It was later decided that Bronx would be more interesting if he acted more like an actual dog rather than a cartoon pooch.
- Another possible name for Bronx was simply "Dog".