Goblins, as a whole, are a bunch of vicious sadistic bastards. Even so, Goblins en masse can be lumped into three categories. The cunning ones, the cowardly ones and the dead ones. You don't survive amongst Gobbos and Orcs without some skills or luck.
The Tribe that marches before you is a triumph of luck over skill or sense. A conglomeration of Night and Forrest Goblins, most often seen under the rule of an Orc or as separate groups raiding and causing mayhem.
Griznog Toofsteela is commonly held to be a lucky Gobbo. His rise to power was not through the normal method of killing whomever had what he wanted, but rather a function of being in the wrong place at the right time. When Gorbug Killzlots exploded due to a bad mushroom beer and accidentally swallowing a squig, Griznog was found in the area looking confused and getting the Squig survivor as a pet. When Murg the Smelly took a long walk off a short cliff, Griznog would have been split in two by Murgs falling sword had he not stopped to cuff Wotwot, a Shaman, around the ear. Instead as if by the hand of Mork, or mebbe Gork, a blade landed beside him.Finally, when he and Wotwot were sent out to beat some sense into a rebelling mob of Night Goblins, they tried to sneak off and instead came across the crushed body of the rebellious leader who had stopped to sneak a stunty beer under some loose rocks. Since then the mob has followed the twosome everywhere out of fear.
"Ere boss.... Wotwot's narratin to 'imself again"
"Yeah so? Give 'im a thump"
"...I'll try boss, but 'e sounds like a humie"
Finally the rabble decided to try joining a passing group of Orcs. This was to be genesis of the tribe. Instead of crushing Griznog or otherwise humiliating him as normal, the Orcs simply laughed at the assorted Night Goblins and told them to come back when they were "ard enuf". Peeling off from the Orc mob, a small unit of Forrest Goblin Spider Riders decided to follow Griznog. Perhaps it was the spirit of Gork, perhaps the command of Mork or most likely just them being hopped up on venom again that caused this.
So the tribe was named, and their plan formed. They would travel far to where the Black Orcs were said to have originated, spawned in some fashion near dark and dangerous Dwarf holds. There they would find out what made the Black Orcs so strong, use it themselves and return truly ard enuf.
Listen now to their tales as they mar*WHACK*aaaaaagh! We iz da best and we iz ...wot? Whyz me 'ead hurtin?