Adaptation Displacement: Panchito's horse, Señor Martinez actually comes from old American newspaper strips written in the 40s which, while popular in some countries, were never reprinted in English until after the publication of The Three Caballeros Ride Again
Anvilicious: Some of the stories (especially War of the Wendigo) move into this territory.
Broken Base: Discussions over whether Don Rosa is Carl Barks' "true" successor or simply one of many writers (albeit a very good one) playing in his sandbox get heated on occasion.
Crosses the Line Twice: A cheapskate who will read a newspaper from a trash can rather than buying one despite having a net worth of $900 billion is surely funnier than a cheapskate with a net worth of a few million who simply treats others like crap for his own gain.
Designated Villain: Surprisingly common. Quite a few stories have Rockerduck actually being far more benevolent than Scrooge, or simply being completely moral. He still always loses in the end.
Scrooge Mc Duck started as a supporting character in Donald's comics, but eventually became popular enough to be spun off into his own series. Scrooge is much more popular than Donald in Finland and France, where the magazine devoted to Carl Barks' universe is called "Picsou Magazine". (Picsou being the French name for Scrooge). DuckTalesputs Donald on a boat in the first episode, reducing a character that was always going along with Scrooge on his adventures to a guest character. Considering Scrooge started as nothing more than a caricature of thrift in a propaganda cartoon during World War II, that's one escalation.
Goldie. Used only once by her creator Carl Barks and far more often by Romano Scarpa, Don Rosa, and others, not to mention her multiple appearances on DuckTales.
How Ludwig von Drake is related to Donald is quite a mystery. He is apparently Donald's uncle, but this would make him either Scrooge's brother or Grandma's son, neither of which seems likely since he is Austrian. Don Rosa has offered the possible explanation that he is married to Scrooge's sister, Matilda. Some German comics have Daisy calling him "Uncle".
Another puzzling relative is Gideon McDuck, a Recurring Character in the Italian comics described as Scrooge's brother. Romano Scarpa's intent when creating him in 1958 was that he'd be simply that: Scrooge's brother, fair and square. However, when Don Rosa wrote his version of Scrooge's youth (which has been accepted as one of the solidest bits of canon out there when it comes to Duck comics), he ignored Gideon, because he did not know about him to begin with. Why Gideon wasn't there at Scrooge's home back in Scotland in his youth remains unknown, but many american fans consider him a half-brother from a brief relationship of Fergus McDuck's after his wife's death. It has sometimes been guessed that Gideon is Scrooge's younger brother, born only after Scrooge left Scotlandnote He is named "Scrooge's younger brother" in the recent american translation of his debut appearance, but it's a deplorably unfaithful translation, despite being also a very funny one, so it can't be counted as canon. A simpler explanation is provided by this Italian family tree◊ where he is simply a cousin ("younger brother" thus likely being a term of endearment).
A few of the comics featuring Scrooge McDuck imply Scrooge and Magica De Spell have what appears to be a mutual attraction. Magica might even have better chances than most villains since Don Rosa's Scrooge actually has had hatesex.
Scrooge's canonical One True Love, "Glittering" Goldie O'Gilt may not be evil as such, but their relationship is antagonistic more often than not.
Rockerduck seems to appear more frequently in Italian comics than Glomgold ever did in American ones.
The Beagle Boys' grandfather appears much more frequently in Italian stories, but that version of the character appears to be solely based on the "Grandpa Beagle" from "The Money Well" and not on Blackheart Beagle from "The Fantastic River Race." Some of the versions make him more kind.
Disney comics in general are known to still be hugely popular in Europe, while they have largely faded out of American culture. Duck comics are no exception, and in fact seem to enjoy even more popularity there than Mickey Mouse ever did. This may be related to these comics being quite similar in style to Franco-Belgian Comics.
The comics are also very popular in Egypt and India, to the point that the characters have become localized pop culture icons. Parents literally pass down the hobby of reading these comics to their kids. As a result, some people have casually accumulated an incredible collection of the comics over decades.
Gladstone Gander in the comics is widely regarded as an insufferable JerkassSmug Snake who delights in rubbing his constant stream of good fortune in Donald's face and never suffers for it, and for whom Daisy is often more than willing to forsake Donald's affections.
Scrooge can also qualify for his jerkass tendencies, particularly for Donald's fans. You'll hear "When will Donald get his revenge on Gladstone and Scrooge?" from Donald's fans quite often. This is part of the reason behind the creation of Paperinik.
Paperinika (Super Daisy), Daisy superhero alter-ego. While abandoned for years by Italian authors after a rather bizarre story, Brazilian authors made her in pretty much The Ace who constantly one-upped and humiliated Paperinik. Because Paperinik was introduced as Donald's chance to escape from his regular Butt Monkey / Chew Toy status, these stories did not go over well with Italian fans. Also, her Straw Feminist characterization made her particularly unlikeable. She is rescued from this status in Ultraheroes where she got a more balanced personality and became more likable to the readers.
Supreme Chef: In some stories, Donald's cooking skills are only surpassed by Grandma Duck. In an Egyptian issue (#592, 4th June 2015) celebrating his 81st birthday, it is explicitly stated among 24 other character traits that describe him.
From the classic Paperinik stories, "Love into Oblivion": Daisy saw him change into Paperinik, so, as usual, he fed her a memory-erasing candy... Except it had been damaged, and made Daisy forget of Donald and believe that Paperinik's her fiancee.
The entire Donald and Reginella love story that is much a tragic love because every time they are forced to stay away by events of the story.
Donald himself skirts the line of woobiehood, especially any time he appears with Gladstone or Scrooge (or even, on occasion, his nephews). It's only partially offset by his own stubbornness and short temper.
Though it's obviously never brought up on panel, there is legitimate horror in Huey, Dewey, and Louie's backstories. They were abandoned by their mother on Donald's doorstep, to be raised by their generally well-meaning but somewhat questionable uncle. And if you throw DuckTales in as canon, Donald himself abandons them. Glimpses of the future suggest he never returns, and he's not mentioned again after the second season premiere. At the very least, one imagines a great deal of therapy in their future.
Don Rosa's "The Life and Times of Scrooge McDuck" series flirts with this portrayal for Scrooge. By the penultimate chapter, it's hard not to feel bad for a man who let his obsession with wealth chase away his family and friends and turn him into a bitter old Citizen Kane expy. Of course, he's very much the author of his own woe, and the story concludes with his reconnecting with Donald and the nephews, so it doesn't stick, but it's a rather depressing insight into Scrooge's character.