Once upon a time, there was a man called Rob Liefeld. Near the end of The Dark Age of Comic Books, his comics began to sell poorly. And there was another man — Alan Moore. He felt guilty, because a couple of his comics drastically changed the industry, when everybody wanted to do something like him, thus giving rise to the Dark Age. Those two men met and saw great opportunity with each other. Everything with Moore's name on it was selling, so Liefeld could save his company by hiring him. On the other hand all of Liefeld's heroes were copies of DC/Marvel characters or teams, and Moore got an idea how to use them to appeal to classic comics fans. A deal was struck, with Liefeld basically giving Moore a carte blanche to do whatever he wanted creatively. At first, they started slowly; Moore got Supreme and turned him into a living love letter to the Silver Age Superman. It worked, so Moore got his hands on all Liefeld's characters. And this is when this story comes to life.
Youngblood: Judgment Day is a 3-issue miniseries (plus Aftermath one-shot) written by Moore and drawn by Liefeld and various other artists. Youngblood team member, Riptide, has been murdered and her fellow teammate, Knightsabre is the main suspect. Because the authorities don't want anything to do with it and it's the first case like that in history, they left the superhero community to handle this, with superheroes as the jury, courtroom, defense, prosecution and judge familiar with the community. But it's all only the beginning of a far greater tale, one older than our world.
- Anachronic Order: Flashbacks in the first issue jump from present to various times in possibly-random order - 1868, 436, 1943 etc. Later issues set them in chronological order.
- Art Shift: All flashbacks are drawn by different artists, some of whom are legendary veterans of the comics medium such as Gil Kane.
- Bittersweet Ending: Sentinel's machinations were uncovered and as punishment, he was sent to Supreme's Hell of Mirrors. The Book of Hermes meanwhile lands with a homeless girl, who is implied will write much better stories than the ones Sentinel did. Unfortunately, Riptide is still dead, and it’s unknown just how many people’s lives were ended or ruined by the "adventures" Sentinel wrote. Given the history of Youngblood till that point, it was quite a significant amount.
- Chewbacca Defense: Defense attorney Skipper calls several witnesses to testify about a seemingly irrelevant detail of Riptide's murder (a book missing from her shelf), completely derailing the trial. Subverted when the alternate sequence of events he proposes, that the theft of the book was the real motive for the murder and the perpetrator was Youngblood teammate Sentinel, actually turns out to be true.
- Cosmic Retcon: The series reveals that the Book of Hermes is capable of changing reality and Sentinel used it to not only rewrite his own life but also turn the whole world into one that he liked.
- Evil All Along: Sentinel was revealed to be the one who was responsible for the vast majority of heroes being so dark, violent, and borderline insane, having rewritten the world with Hermes' book to match his ideas of what superheroes were supposed to be like. To that end, he kills Riptide and frames Knightsabre to get the book back and resume his control.
- Future Me Scares Me: Though they haven't met, when young Marcus Langston got his hands on a book that contains all stories of everybody in the Universe, he read his own story and was horrified with the revelation that he was going to become a junkie and criminal, so he rewrote it, making himself a superhero and member of Youngblood - Sentinel.
- Internal Deconstruction: Alan Moore basically uses a metatextual rundown of comics history and the crossover to take the piss out of Rob Liefeld's influence on The Dark Age of Comic Books. Specifically, Sentinel's rewriting of reality was based on his own malformed teenage perception of what superheroes should be like, corrupting the idea of superheroes into gun-toting, scowling maniacs that are more akin to villains than the actual heroes of the past.
- Make the Dog Testify: Toby "Skipper" King eventually calls to the stand Giganthro, a member of the time-travelling League of Infinity. Giganthro is a mutated caveman incapable of speaking any modern human language, though he understands well enough. Thankfully, team leader Zayla Zarn provides translation for his testimony.
- Metafiction: All over the place, with everything being a part of a story and a man who travels through imagination visiting to see what new stories are going to happen now.
- Mighty Whitey: Zantar, White God of the Congo. This is almost endlessly Lampshaded by the casually racist narration during his part of the story, and later by one of his own descendants.
- Most Common Superpower: Lampshaded by a superheroine from sixties who says that she was considered as well-endowed back in the days, but compared to today's heroines, she feels flat-chested.
- Only Known by Their Nickname: Bryce Barstow, formerly the Fisherman, calls his former sidekick Toby King by his old hero name, Skipper - despite being his adoptive father. Toby's a little irritated, but settles the matter by saying he'd prefer his real name in this situation.
- The Perry Mason Method: Toby King relentlessly pursues the details behind a book missing from Riptide's room after her murder, gradually uncovering an intimate connection between a certain member of Youngblood and that book. This eventually causes Sentinel to fly into a fit of rage and attack King; he grabs at the book and curses King for ruining his plan, outing himself as the murderer.
- Plot-Triggering Death: Riptide's death is what gets the plot going. She doesn't even actually appear in the series until after she dies.
- Putting the Band Back Together: After the end of the trial and the government pulling Youngblood’s funding, Diehard proposes bringing back the Allies, the Awesome Universe's equivalent of the Justice League of America. The former members of the team are all enthusiastic about rejoining.
- Reality-Writing Book: The series revolved around a mystical book. Anything written in this book became reality.
- Rewriting Reality: The series dealt with a mysterious book that could warp reality. Writing in the book would cause what the writer had written to come to pass.
- Smoking Gun: Toby King introduces the book of Hermes, a book containing all of history that can be used to alter the future — or the past. He'd spent the entire trial trying to prove that the theft of the book was the true motive for Riptide's murder, and finally had proof of both this and his client Knightsabre's innocence: a passage written by Sentinel to implicate Knightsabre in the crime, as proven by the fact that it describes him writing it.
- The Smurfette Principle: Invoked, where Glory is keen to the idea of re-forming the Allies of Justice because she enjoys being the only woman in a team of men — it's implied that it makes her feel like she's the one in charge.
- Stable Time Loop: It's mentioned that the League of Infinity first heard of Giganthro through historical records of the trial... where they helped their longtime friend and teammate Giganthro testify.
- Take That!: The core of the story is a rejection of the gritty, "extreme" heroics of Youngblood, emphasized when the previous adventures of Youngblood were described by Toby King as "heroes motivated only by money or psychopathology stalked a paranoid, apocalyptic landscape of post-nuclear mutants and bazooka-wielding cyborgs". The climax of the story reveals that the entire original series was basically a childish Self-Insert Fic written by Sentinel.
- The Trope Kid: The Brimstone Kid. He was a gunslinger who sold his soul to the devil in exchange for unbeatable gunslinging skills.
- Wham Episode: The series was this for Youngblood - Knightsabre is accused of killing Riptide, team is disbanded and entire Universe turns out to be have been plunged into Darker and Edgier setting by a magic book.