Bronx was hatched in the year 978 in the rookery of the Wyvern Clan, and quickly grew to become a formidable "watchdog" for the gargoyles, resolutely defending Castle Wyvern against its enemies.  He survived the Wyvern Massacre in 994 because he had been sent down to the rookery with the trio by Goliath for getting into a fight with some of the humans, and was afterwards locked into a stone sleep by the Magus, only to be re-awakened a thousand years later when Xanatos moved Castle Wyvern to the Eyrie Building. ("Awakening: Part One", "Awakening: Part Two")
Bronx took less part in the clan's adventures than did the other gargoyles, largely because he lacks wings; he stays home, instead, and snoozes beside Hudson's recliner. In fact, Bronx spends most of his time there sleeping (occasionally on Lexington's magazines when Lex wants to read them). He also has a formidable appetite, and will eagerly eat anything as long as it counts as food.
But Bronx is still a redoubtable fighter (if his "stay-at-home" role gives him less opportunity to display it). He can successfully intimidate the gargoyles' opponents when he charges at them, growling, and has powerful jaws. He is particularly vicious against robotic foes. This may be due to his being attacked by a Steel Clan robot shortly after being re-awakened. ("Awakening: Part Five") He quickly helped destroy that robot and has attacked most robots ever since. He once chewed half the face off Coyote 1.0 (giving it its distinctive half-human half-robot visage that all future Coyote robots have borne), and he also tends to growl at Coldstone when he seems to shift personalities. ("Leader of the Pack", "Legion") Bronx's ferocity in battle makes him a valuable member of the clan. He is also an excellent judge of character and extremely loyal, trusting those who are true friends of the clan and growling in a very hostile fashion at enemies, even enemies pretending to be friends (the only exception was when Demona was able to calm him by speaking in a soothing voice, even though she was threatening to kill him and the entire clan). Bronx also has an excellent sense of smell and has come in handy when his clanmates needed assistance in finding someone. ("City of Stone" Part Four)
While Bronx's adventures in New York City were few, he did accompany Goliath, Elisa, and Angela on the Avalon World Tour. He displayed his useful olfactory abilities when he tracked down the werepanthers Fara Maku and Tea Gora to Kara Digi during his stay in Nigeria. ("Mark of the Panther") But his greatest adventure of the Avalon Tour came when he met Rory Dugan in Ireland, and helped him realize his true destiny as the reincarnation of Cu Chullain so as to save his companions from the Banshee. Bronx may, in fact, be the reincarnation of the Hound of Ulster. ("The Hound of Ulster")  He is also one of the few gargates that has at one point remained as flesh during daylight. This occurred when he found the Obsidian Pendent linked to the Mayan Sun Amulet and held on to it after sunrise. ("The Green")
After his return from the World Tour, Bronx had an adventure on his own while Goliath and Hudson battled Hakon's ghost and Wolf and Angela and the trio helped Elisa take down Tomas Brod.  Cagney may have accompanied him on this adventure. 
Bronx hates pigeons, with an almost savage fury. 
Note: This character does not speak, therefore he does not have any lines.
Voice Actor: Frank Welker
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". 
Bronx had a (chibi-form) cameo in "Pizza vs. Fireworks", the opening episode of Disney's "Chibiverse" series.