Della Duck to Scrooge McDuck. Scrooge is the adrenaline junkie, but even he knows when to stop and listen to his family, that they come first. He's survived to be a hundred and fifty years old by knowing when he's gone too far. Della never learned that lesson, and got trapped on the Moon for it.
Della Duck to Donald Duck. While their basic personalities aren't that dissimilar — they're both Hot-Blooded, stubborn, and impulsive Determinators with a tendency towards Didn't Think This Through — their attitudes and priorities are pretty much opposite: Della is a Broken Ace, Donald is a Crouching Moron, Hidden Badass. Della is a perpetual optimist with a sunny disposition and a reckless streak a mile wide, while Donald is a pessimistic worrywart who's far easier to knock out of balance, and who's a lot more cautious and overprotective. Della is a big dreamer always chasing the next adventure while Donald is far more down-to-earth and finds more pleasure in the small things. And of course, thanks to Della having been gone for so long and leaving Donald to raise the triplets, Donald is an experienced and responsible parental figure while Della is irresponsible and has no clue how to be a mother.
Going further, Donald and Della have almost completely opposite approaches to the children during adventures, leading to her episodes having an opposite flow from his. Donald is very protective and dislikes the idea of the kids going on adventures, but knows them well enough to trust them to take care of themselves in a dangerous spot. Della, meanwhile, loves the idea of taking the kids on adventures, but is petrified of losing them and becomes even more fearful and overprotective than Donald is when danger strikes. This comes to a head when both of them lead the kids together in Moonvasion: Donald - the responsible one - is ready to help the kids make a crazy plan, while Della - the impulsive one - wants to hide everyone forever on a deserted island.
Each of the three nephews represents Scrooge's main aspects in different ways.
Huey is smarter than the smarties, but to the point where he has a need to alwaysbe smarter.
Louie Duck to Scrooge McDuck. Scrooge's point of pride is that he made every penny of his fortune through hard and honest work. Louie would prefer his desired fortune to be handed to him on a silver platter. He hates the idea of working hard for a good life and much prefers to get it through scamming and trickery which is why he asked Goldie to make him her apprentice. "The Richest Duck in the World" also demonstrates that unlike his uncle, Louie is considerably more humble and willing to admit his faults, unlike the prideful Scrooge. It's what results in Louie being able to end the Bombie curse after a day, while Scrooge had resorted to keeping the monster trapped in a bin for decades to keep the curse at bay.
Webby Vanderquack to the triplets Huey, Dewey, and Louie— All four of them were raised by an overprotective guardian, but while the triplets grew up to be well-adjusted, Webby became socially impaired. On the other hand, the triplets know very little about their family, while Webby's favorite hobby is studying their family's past and exploits.
Bentina Beakley to Donald Duck. To Donald as an overprotective guardian. Donald is a worry-wort, while Mrs. Beakley trained Webby to be "ready for anything". Additionally, while Donald doesn't like the idea of his nephews going on adventures, Mrs. Beakley is perfectly fine with Webby going on adventures with Scrooge as long as she doesn't lie about it because she knows she'll be safer with Scrooge than anybody else; Donald, on the other hand, does not trust his uncle (and with good reason). Inversely their parenting styles have different effects on their children; Donald may be a worrywart, but Huey, Dewey, and Louie are well-adjusted, whereas Mrs. Beakley trained Webby to be "ready for anything" but never let her leave the mansion until the nephews came, meaning she has No Social Skills and has no idea on how to act in a normal setting.
Gladstone Gander to Donald Duck — While Donald is an unlucky but hard-working, Jerk with a Heart of Gold, Gladstone is a straight-up lazy, arrogant jerk who relies on his luck to see him through any conflict.
Gladstone Gander to Scrooge McDuck — While Scrooge earned every penny of his vast wealth, Gladstone's luck allows him to live a carefree existence without having to work for anything he has.
Gladstone Gander to Louie Duck — Both are lazy and selfish (and wear green!), but Louie is undergoing character development by being put into situations where he has to apply himself whereas Gladstone appears incapable of either growing as a character or actually applying himself... even when the situation demands it.
Fethry Duck to Donald Duck. Like Donald, Fethry has a bit of a hard-luck life. Unlike Donald, he's upbeat and cheerful and tends to meet adversity with good humor, unlike Donald with his bad temper.
Fethry Duck to Gladstone Gander. Both are considered the Black Sheep of the family — but while Gladstone is a selfish jerk, Fethry means well but is eccentric and over-enthusiastic in sharing his esoteric interests.
Fethry Duck to Huey Duck. Fethry is an eccentric and nerdy Junior Woodchuck who is obsessed with gathering arcane knowledge and has a fondness for red-colored clothing and hats. Unlike Huey, who is focused and organized, Fethry is a scatter-brained, disorganized, and impulsive Cloud Cuckoolander.
Lena De Spell to Louie Duck. Lena is this to Louie to some extent, both have a Toxic Friend Influence to Webby and have bad kid attitudes, but have some differences when it comes to family, Louie at least has a family who cares about him, while Lena has a bad relationship with her aunt.
Zan Owlson to Scrooge's Board of Directors. While both are concerned about unnecessary funds and the PR damage of what their prospective eccentric superior could do to their companies, the key difference is that Owlson is also interested in making money, actively bidding on new contracts. By contrast, Scrooge's Board is concerned about cutting costs and only cutting costs; Scrooge is the one who actively bids on contracts and is always looking for new ventures. In addition, while Zan has good intentions and actually cares about other people, the Board are actually the F.O.W.L. high command.
Zan Owlson a businesswoman who took over Glomgold's company temporarily in season 2, is this to all the male CEOs in the series, being the only one of them who doesn't let petty grudges occupy her time and her company's resources.
Magica De Spell to Scrooge McDuck. Both of them are experienced adventurers who are well-versed in the world of magic and are known to collect special artifacts during their quests. But while Scrooge is more sensible with the artifacts and knowledge he gains, Magica intends to use them as a means of obtaining power.
General Lunaris to Louie Duck. Just like the evil triplet, Lunaris uses underhanded tactics and quick-thinking skills in order to manipulate others into following his schemes. He also puts a lot of effort into "seeing all the angles" when creating his plans so that nothing can take him by surprise. The obvious difference is that Louie is a child who doesn't mean to hurt anyone with his get-rich-quick schemes, while Lunaris has no issue with hurting anyone who would stand in the way of his world domination scheme.
General Lunaris to Donald Duck. Lunaris is calm and collected most of the time and has apparently never forgiven his father for being scared of the earth, while Donald (and incidentally, later Louie and the other triplets) had a falling-out with Scrooge over blaming the latter's Thrill Seeker tendencies for losing Della but has since made up with him and he has legendary anger issues.
Scrooge McDuck to Flintheart Glomgold. While Scrooge believes in making his money fair and square, simple plans, and working smarter rather than harder, Glomgold made his fortune through cheating and stealing, has a Complexity Addiction, and prefers to work harder rather than smarter. Also, Scrooge is actually Scottish, while Glomgold is South African but pretending to be Scottish and his accent is entirely fake. Along with his beard..
Glomgold's also a billionaire duck with a Scottish accent, but Scrooge earned his wealth "fair and square", whereas Glomgold earned his by cheating and stealing.
While Scrooge works on a "Work smarter, not harder." mentality, Glomgold seems to go with the opposite "Work harder, not smarter." Glomgold's determination to get what he wants by any means possible, no matter what, often leads him to undermine himself and his business.
Glomgold tends to let his penchant for complex plans overrun his judgment and motivations, while Scrooge prefers the smartest, simplest way of doing things.
Scrooge McDuck to Mark Beaks. Scrooge is "tougher than the toughies, smarter than the smarties, and sharper than the sharpies" and made his money fair and square, while Beaks is Brilliant, but Lazy and committed fraud in order to make it to the billionaire mark.
Mark Beaks to Flintheart Glomgold - Both have Faux Affably Evil going for them when they want to keep up appearances, but Glomgold is more concerned with one-upmanship and revenge while Mark Beaks is 100% dedicated to appearances. Also, Glomgold is an unapologetic thief while Beaks is a Con Artist.
Mark Beaks to Huey Duck - Both are big on well-laid plans and checklists, but there's a short-lived hint that Mark Beaks is quite a bit more uptight about deviations from his than even Huey. Plus, Huey makes his plans to help others as well as himself, while Mark's plans only help himself.
Mark Beaks to Dewey Duck - Take Dewey's love of attention, exaggerate liberally, then subtract redeeming qualities and concern for others and you're 90% of the way towards getting Mark Beaks.
Mark Beaks to Louie Duck. Even if Louie didn't appear in Mark's debut, it's clear that they both have a similar Laissez-Faire con artist attitude towards earning money, since Mark's entire plan with Project Tah-Dah is the epitome of "Get something for nothing" that Louie has shown to admire in the past. However, Mark is far more self-absorbed than Louie, while Louie is more laid-back and is more comfortable admitting his own faults.
Mark Beaks to Gyro Gearloose - Both of them are tech geniuses, but while Gyro has lots of original ideas while being a very unfriendly person with No Social Skills, Beaks scams people and steals their ideas while caring a lot about public appearances and being very chummy with everyone. Their contrast is highlighted best in "Who is Gizmoduck?!" where Fenton works for both of them for a while.
“Ma” Beagle to Scrooge McDuck. Both of them are the main figureheads of their respective badass families. But while Scrooge actually cares about his family and encourages them to do noble and meaningful deeds, Ma belittles and abuses her kids and pushes them to be master criminals such as herself.
F.O.W.L. to Glomgold's short-lived Legion of Doom from "Glomtales!". Both groups consist of enemies to the members of the Duck-McDuck family. However, Glomgold's group consisted of more noticeable and high-profile villains, while F.O.W.L. employed individuals who could slip under the radar easily. Not to mention most of Glomgold's "family" (sans Ma Beagle) are either Laughably Evil, incompetent, and slow-witted Leeroy Jenkinses or have become less of a threat than they originally were. The notable members of F.O.W.L. however, while flawed to some extent, keep their cool and effectively follow through with their plans.
Jeeves to Duckworth. Both of them are highly competent butlers to their respective billionaire employers. But while Duckworth was lean and a Servile Snarker, Jeeves is the silent type with a muscular physique. Their differences even extend to their appearances after life with Duckworth becoming a ghost-demon while Jeeves becomes a zombiesque brute.
Doofus Drake to Louie Duck. Doofus is just as rich and spoiled as Louie wants to be - and is pretty much what Louie would become if he didn't love his family.
Both Donald and Goofy often find themselves and their families in extraordinary situations, with Donald on dangerous family adventures and Goofy's clumsiness causing accidents and disasters. But while Donald gets stressed out because of them and constantly wishes his family were more normal, Goofy takes it in stride and accepts that his misadventures are just normal for him.
The Phantom Blot to Scrooge, regarding their views on magic. Both have a distaste for it, but while Scrooge is willing to acknowledge that good things have come from it (Lena, for example), the Blot refuses to see it and anything created by it as anything but Always Chaotic Evil.
In spite of them not being in an episode together, Zeus to Jormungandr. Both are gods that share an antagonistic relationship with the Ducks and are Attention Whores. However, Zeus is a Sore Loser who caused most of his own people to walk out on him, while Jormungandr is a Graceful LoserNoble Demon who is beloved by the people of Valhalla until the end of the episode.
Glomgold to John D. Rockerduck. Both of them are rich ducks who made their fortunes through dishonest means and come to blows with Scrooge in their efforts to become wealthier. However, whereas Glomgold is rotund, bombastic, has many colors in his usual attire, and makes no small show of what kind of person he is, Rockerduck has a more average build, is much more calm and polite in speech and mannerisms, wears almost nothing with color on his person beyond his yellow boutonniere, and prefers to put up the facade of a respectable tycoon aiming to make any town he visits a thriving metropolis while actually swindling the residents out of their mineral rights and leaving them broke once he's gotten what he wants out of them. Also, while Glomgold first encountered Scrooge when the former was a child and the latter had gained his status as the richest duck in the world, Rockerduck first came into conflict with Scrooge when the latter was hoping to strike it rich during the old west. While Glomgold came from humble beginnings, Rockerduck is, as he claims in "The Split Sword of Swanstantine", the heir apparent to the Rockerduck fortune.
Daisy to Donald. Both have a Hair-Trigger Temper and similar issues about being ignored and dismissed while just trying to make their way in the world, but their temperaments are different. Donald is more of a Jerk with a Heart of Gold who is outwardly testy but has a not-so-hidden good heart when it comes down to it and completely flies off the handle when his temper flares up. While Daisy is a Nice Girl who can bring her temper out the second something goes wrong and tries to keep it focused and controlled so she doesn't cause more problems. This also applies to their fighting styles. Donald is Unskilled, but Strong, channeling his Unstoppable Rage into overwhelming force to take down enemies, while Daisy is Weak, but Skilled, carefully focusing her hits so they do the most damage.
Emma Glamour to Mark Beaks, who happens to be her son. She's a huge social media presence and just as much of a Jerkass as he is, but how she goes about things is the complete opposite. Whereas Beaks acts very affably to hide how exploitative he really is, Emma is fully upfront about her cold behavior, and makes it very clear how high her standards are. Also, while Beaks treats anyone who can benefit him as a disposable tool, Emma is genuinely on the lookout for the next big trend and will give credit where it's due if someone impresses her. Emma's also shown to put in the work to do her job, while Beaks lies and steals to do his.
Zeus to Scrooge. Both are heads of their families. Best shown before the games in "The Spear of Selene!" while Scrooge gives Huey and Louie advice on how to beat Storkules and that he believes in them, Zeus just brags to Storkules about the glory his winning will bring him.
Jim Starling to Drake Mallard, Jim being a mean actor playing a heroic figure in contrast to Drake being a Nice Guy playing an Anti-Hero and both end up in opposite paths.
Steelbeak to Launchpad. Both are Dumb Muscle and The Big Guy on their respective sides who have insecurities about being seen as stupid by others, but Launchpad is also a Nice Guy who deeply cares for his friends and is loyal to his boss Scrooge, while Steelbeak seems not too fond of his superior Black Heron who also sees him as a plague. Additionally, both of them become Genius Bruisers thanks to the intelligence ray, while Launchpad uses his new-found intelligence to save Duckburgh and sacrifices this persona willingly, Steelbeak uses it for his ongoing evildoing.
