Twer is the representative for the Traders on the Foundation Council. He accompanies Mallow on his journey to Korell and protests Mallow's treatment of the missionary. After that he kind of just disappears from the story. Mallow mentions him during the trial, pointing out that Sutt had him under his control the whole time, but other than that, poof, the man just vanishes.
In terms of story, Twer is there for the foreshadowing. When Mallow throws the missionary to the Korellian police, Twer argues that Mallow's duty is to protect the priest. But Mallow can be a pretty convincing guy with a blaster in his hand, so Twer doesn't exactly win the debate.
Twer's argument also hints at the relationship between custom and law. It seems like most people see custom as equal to if not superior to the law. This really matters later, as Mallow battles love of custom in both his trial and his during his tenure as mayor.
Jael becomes Mallow's partner in politics when the Trader returns to the Foundation. With Jael's help, Mallow becomes the mayor and in turn Jael becomes the Minister of Education and Propaganda.
With a job title like that, you'd better be careful how you file your paperwork.
Based on the above description, you'd think he'd be an important fellow, but once again, not so much. Jael doesn't do much helping that we ever see—though he probably helps a lot in the missing parts of story between chapters. Instead, his story role is to be present whenever Mallow does something. That way, Jael can ask questions to better understand the situation, meaning the reader can better understand the situation as well. Thanks, Jael!
Wife to the Commdor and daughter of Siwenna's viceroy. The Commdora's daddy married her to the Commdor to establish an alliance between Korell and Siwenna, something she's not too happy about. She bickers a lot with her husband and is in no way submissive verbally—although socially her husband always has the upper-hand.
She only appears in two very small chapters, meaning it's hard to get a grasp on her character. Is she a strong female character? A victim of circumstance? A villain?
She's also the Foundation trilogy's only female character until the appearance of Bayta Darell in the second half of Foundation and Empire. Now that we think about it, the complete absence of sexual politics in Foundation kind of says a lot about sexual politics, doesn't it?
Barr is an old man living in a desolate part of Siwenna. A one-time scholar, he now lives as a hermit after a glory-hungry admiral destroyed his city, killing five of his six sons and leaving his daughter's fate unknown. Major bummer.
In the grand tradition of minor characters, Barr provides us with some helpful info. He clues Mallow into the inner-workings of Siwenna and the current state of the Empire. Conveniently, he clues us in, as well.
Barr's current predicament also helps the reader see the difference between the Foundation and the current state of the Empire. The Foundation would have provided Barr with a job and put a smart, capable man to work. Not the Empire. The Empire is run by power-hungry men who would rather take and destroy than give and create.
Although we never meet Ocam again, his sixth son, Ducem Barr, appears in Foundation and Empire, playing a pivotal role in the war between the Foundation and the remnants of the Galactic Empire. So that's something?
The tech-man maintains a nuclear generator on the planet Siwenna. Mallow bribes him to get a small tour of the generator to discover the Empire's true nuclear capability.
But it's not like he's a nuclear guru, or anything. He was born into his job, meaning he didn't have to go to school and actually learn anything. This, along with the tech-man's ignorance of how the nuclear reactor actually works, tells us that the Empire is in serious trouble. Unlike Foundation scientists, the tech-man—here representing the Empire—can no longer innovate technology or learn anything new in science. Instead, he figures that what has worked in the past will always work in the future.
But as anybody who has ever owned a car can attest, there's no guarantee that what runs today will run tomorrow.
The Foreign Secretary, Purveyor of Holy Food, and Master of the Temples. But don't be fooled by all those fancy titles; this guy doesn't do much. Basically, he sits at Sutt's apartment and sips wine while Sutt monologues his plans to him. So, this character's purpose in the novel is less about being a character and more about being someone to receive important plot information for the reader. Fun times.
Both men are soldiers aboard Mallow's spaceship the Far Star. They're fiercely loyal to Mallow and basically follow his commands. Although Demen messes up by bringing the missionary aboard without Mallow's permission, he accepts his punishment like a good boy. Tinter hides the Far Star long enough for Mallow to visit Siwenna. And that's that.