Big Stogg was always a little smarter than those like him ought to be according to the boss. One day he was caught doing numbers and letters all fancy like, so he crushed the boss-mans' skull, gathered up his lads, and set off to crush the skull of anyone else who got in his way.

Turns out Big Stogg was born with an analytical brain and a love of people watching. He taught himself to read and write and do numbers. Though anything too complex still gives him a headache. But underestimate him at your peril, at the negotiation table he's a force to be reckoned with, both smarter than anyone expects and capable of punching your spine out through your back.

Big Stogg's little brother (Mama Stogg wasn't a quitter), though calling him little Stogg didn't feel quite right, so he was named Medium Stogg. He has an actual name, but he got bored of correcting people quickly and his new name stuck.

Not the smartest bulb in the manufactorum even before the lobotomy. This doesn't really matter cause as he sees it, his muscles do all the thinking for him.

The lobotomy process unlocked some strange buried ancestral memory and now Clodpoll whistles as he works, talking about defying gravity and railway phelynxs if ever asked about the tunes.

Numbskull's not actually lobotomised, he just think the helmet looks cool.