Adored by the Network: Averted. Contrary to 1990s comic book tradition, the massive success of the first Ultimate comics was not followed by an orgy of "Ultimate whatever" titles. The line always had a short and limited number of comic books being published at a given time, and some self-contained miniseries.
All-Star Cast: Mark Pannicia described the post-Ultimatum artists of Ultimate Marvel as such. Bendis, Hickman and Spencer were described as "three amazing writers", and Esad Ribic, Sara Pichelli and Paco Medina were described as "some of the best artists in the industry".
Colbert Bump: Although the Ultimate Marvel universe was a success, it was just a success inside the niche market of comic books. But then, the first stages of the Marvel Cinematic Universe increased its notoriety by taking a strong influence from its looks and feel.
Doing It for the Art: The main thing of the Ultimate Marvel, from day one to its very end, was to take creative risks and try things that would never be attempted in the prime universe. Some of those attempts were lauded successes, such as The Ultimates (The Avengers as a state-sponsored group), others were largely failures such as Ultimatum (a Kill 'Em All event, even killing for good all the X-Men's sacred cows), but the risks have always been taken.
Exiled from Continuity: In the first years and for most of its duration, the Ultimate universe was off-limits to crossovers with the main universe.
Initially, the Ultimate universe was off-limits to crossovers with the main one. This rule was broken with Spider-Men, as it was the 50th anniversary of Spider-Man.
There was an in-house rule about Punisher in Marvel: he will never, ever, kill an innocent, not even by accident. Marvel has rejected and archived several stories with this theme, by many authors. But Ultimate Marvel is the place to break all the rules, so yes, he killed an innocent by accident. And not just anyone: Peter Parker, Spider-Man
God Does Not Own This World: Millar and Bendis eventually left Marvel Comics, and do not have any further influence or control over the Ultimate Marvel universe or their characters.
Magnum Opus Dissonance: When he was hired, Bendis (who only had experience in indie comics before this) did not think that the Ultimate line would do very well. Not because of the project, but because of the context of Marvel Comics itself: back in 2000 there was no MCU (and no Spider-Man franchise in Sony, and the first X-Men film was about to be released), superheroes were completely unrelated with the tastes of teenagers and young adults, and Marvel was still nearing bankruptcy and trying to prove that We're Still Relevant, Dammit!. He said that "When I got hired, I literally thought I was going to be writing one of the last if not the last Marvel comics"
Running the Asylum: When Jonathan Hickman was hired to write the Ultimates, he said this: "I was pretty exited. When I first started at Marvel, one of the gigs I had looked at as a king of homerun job was the Ultimates. I loved how Brian and Mark had started things off - how real and large the world felt - and I always thought there was a logical next step to be taken. So here we are, one small step..."
Schedule Slip: Several titles have fallen victim to this, including Ultimates during vol. 1, New Ultimates, and Ultimate X. Ultimate Wolverine Vs. Hulk takes the cake, with four years passing between issues 2 and 3.
Shrug of God: The Ultimate Marvel universe was destroyed in 2015, during the Secret Wars crossover. Reed Richards was shown restoring the multiverse in Marvel Legacy, and the Ultimate Marvel universe was confirmed to be back in the ending of Spider-Men II. Tom Brevoort was asked about their plans for it at the C 2 E 2, and replied "Well be vague and mysterious there are always plans".
Star-Making Role: The work in the Ultimate comics turned Bendis and Millar into the big authors that they are today.
Unintentional Period Piece: The line as a whole, but especially any part written by Mark Millar. Constant references to mostly now-forgotten celebrities and events, Comic-Book Fantasy Casting all over the shop, and most famously, the "You think this letter on my head stands for France?" moment, when America was disdaining France for not joining in the Iraq War (just a few years later, public opinion turned strongly against the war).
Working Title: Before settling for the "Ultimate" name for the inprint, the name "Ground Zero" was also considered.
Civil War was initially drafted by Millar as a story for the Ultimate universe. But the editors liked it so much that it was turned instead into a Crisis Crossover at the mainstream comics.
Originally, Grant Morrison was going to pen an Ultimate Universe adaptation of The Kree-Srull War, which would have revealed the enemies the Chitauri were fleeing from in The Ultimates Volume 1 as The Kree and that the original Super-Soldier serum was made by Kree Scientists (who had been in hiding on Earth) from Chitauri DNA. However, Morrison returned to DC and this mini-series and the plot-lines it planned to introduce were thus abandoned.
Before Jeph Loeb came aboard, Mark Millar planned to follow up The Ultimates Volume 2 with an ongoing series titled Ultimate Avengers, which would have detailed the original Ultimates team (now called by their mainstream name of The Avengers) operating independent from SHIELD out of Stark's New York townhouse. Millar later recycled story ideas he had for this series into the actual Ultimate Avengers series he would later pen.
When he was first announced for the Ultimate Fantastic Four, and still ignoring that he would have a short run, Millar announced that he would use Dr. Doom and Galactus in the first year. Only Doom appeared. Galactus would be used in Ultimate Galactus Trilogy, by Warren Ellis.
Writer Revolt: Mark Millar made a big success with Ultimate X-Men. Marvel proposed him to write a spin-off comic, Ultimate Wolverine, but Millar wanted to make the Ultimate The Avengers instead. On the other hand, Kurt Busiek, the writer of the Avengers at the time, did not want that to happen, as he feared that the regular Avengers would be left under the shadow of this new comic book. As the Ultimate universe was turning into a Cash Cow Franchise, so badly needed by Marvel to get rid of the risk of bankruptcy, they allowed Millar to work with the Avengers. And yet, the new team got a different name, as Busiek requested, and was named "The Ultimates". Still, it was not enough for him, who resigned from writing the Avengers as a result.