"Let's see, I have a family that should control agriculture, food and drink, financing and theives. What crest should I give them?"
"How about wheat? Or maybe fish if it's maritime?"
"Nah, let's go with snakes and swords!"
"A bit weird, but I guess the snake sort of fits the whole thieves+loanshark aspect. Even if it's very peculiar to decide to have that as your forward-facing persona on your crest."
"Ok, now I have a family that does crafting, R&D, etc. What crest for them?"
"Hmm, maybe vials? Or Hammers? Some bathrobed magician holding a large fireball above their head?"
"Too late, I already picked fishes for them!"
"What? ...Why? No seriously, why?! They had nothing to do with food, did they? You are messing with us aren't you?"
"Now we have the family handling general goods, appraisal services, drink (again), and I guess also adventurers guild. They are the weakesy. Crest?"
"An eyeglass? And maybe a sack or backpack? That would fit the general goods aspect, and even their minor venture into adventuring. And let's add a beer mug, or casket, or maybe wine-bottle, for the liquor aspect."
"Nope, it's going to be a two-faced wolf surrounded by stars. To show that they are ruling over 7 others. And really give focus to the adventuring bussiness, the other parts don't matter."
"But wasn't that the 'oh, and I guess also...' portion? And what do you mean, vassals? Weren't they the weakest faction?!"
"This last family does soldiers & law enforcement, crest?"
"sarcastic voice Oh I don't know, maybe a hammer and some wheat? And maybe a backpack too?"
"How does that fit?! I'll give them a sword, shield, and some prideful-looking predatory bird!"
flips table
"FUCK YOU! I'm gonna murder you, I know where your letterbox lives and where you park your slippers, I'm heading there right now, just wait for a minute!"