The CW's Arrow-verse is constantly in flux. Once, Arrow was the big fish in a small pond. Then The Flash became top dog in this shared DC Comics universe. Now that it spans four ongoing shows (with another likely on the way), keeping up with the Arrow-verse is no easy task. But for those who do, there's little question of which of these four superhero shows currently rules the roost. DC's Legends of Tomorrow has been the reigning champ all season long.

Course Correction

Shorter Length

Better Villains

Also the best-dressed.

Lighthearted Tone

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His name is Barry Allen, and he's the most miserable man alive.

But how did Legends suddenly become king of the hill? And how can the other Arrow-verse shows learn from its example? Let's break down the reasons why this young series improved so much in its second season.We enjoyed the first season of Legends quite a bit, but the show was hardly without its problems. Many of those problems revolved around the core conflict between Vandal Savage, Hawkgirl and Hawkman. In terms of acting and dramatic weight, these three characters were the show's weak links, and the overarching storyline often suffered as a result.Frankly, Legends' second season improved immediately and significantly because these three characters were cut from the plot. Savage was killed (three times over, no less) and the Hawks were written out of the picture in the Season 1 finale. That left the show free to regroup, focus on those characters that worked and bring in a few fresh faces to boot. And we're pleased to note that newer team members Citizen Steel and Vixen have been far more enjoyable additions to the roster.This season even kept Rip Hunter out of the picture for several months. While Rip was one of the stronger characters in Season 1, his absence allowed other characters like White Canary to rise up and fill the vacuum he left behind.That represents of one Legends' unique strengths. Because it's an ensemble show rather than one that revolves around a specific main character with a specific mission, the writers are free to shake up the formula more between seasons. No character feels truly safe. Even now, we don't know how many of the current members will be sticking around for Season 3. Will Vixen return to her own timeline and accept the dark future awaiting her, or will she defy fate? Did Heat Wave's betrayal of his teammates in "Fellowship of the Spear" mark the end of his tenure as a Legend? We never know for sure when the next drastic change will be coming, and that unpredictability makes the show that much more exciting to watch. Couple that with a general premise that involves the Legends travelling throughout time, and there's a variety to this series that the other Arrow shows are hard=pressed to match.Legends is notable for having shorter seasons than its Arrow-verse siblings, with Season 1 spanning 16 episodes and Season 2 increasing to 17 (after an initial order of only 13). On one hand, it's a little frustrating that the best Arrow-verse show is also the shortest. But it's worth questioning whether Legends is good precisely because it has fewer episodes.Let's face it - too many otherwise good shows are guilty of overstaying their welcome each season. Even the Netflix Marvel shows tend to feel a little padded out at 13 hour-long episodes per season, and most of the Arrow-verse shows run nearly twice that every season. Especially when you look at the drawn-out Savitar conflict on The Flash this year, it's hard not to wonder how much things might have been improved by trimming a few episodes and streamlining that conflict. The same for Supergirl and its often meandering Cadmus storyline.With Legends, there's less room for filler or fluff. Sure, we still get the occasional episode that falls back on the standard "travel to the past and rescue this famous historical figure from the Legion of Doom" formula, but generally even those episodes have managed to advance the larger narrative. Nearly every episode this season has contributed something meaningful to the bigger picture, whether that involves bringing the Legends closer to their goal of reclaiming the Spear of Destiny or exploring the various personal struggles our heroes face as time-displaced outcasts and misfits.The shorter season length also helps Legends consolidate its resources. It's an expensive series, to be sure. You have an entire team of superheroes, several of whom have pretty flamboyant metahuman powers. And where The Flash, Arrow and Supergirl usually remain confined to the same downtown Vancouver setting each week, Legends is constantly dragging its cast from one far-flung time period to the next. Add another half dozen installments to the mix, and suddenly we might be seeing a lot more cheap, pointless bottle episodes.As we mentioned, Vandal Savage was one of the main weak points in Legends Season 1. Unfortunately, the show didn't do a particularly great job of adapting this immortal tyrant from page to screen. But Season 2 has made up for that in a big way by introducing the Legion of Doom. Rather than attempt to introduce a new mastermind villain this season, the writers chose to pull from some of the best Arrow-verse villains of years past.At first glance, this might seem like a lazy way of building a new conflict. Reverse-Flash, Malcolm Merlyn and Damian Darhk each had their time in the spotlight, right? But that's kind of the point. Individually, these villains failed to achieve to their goals. Eobard Thawne failed to defeat his greatest enemy, and now he's a refugee from a timeline that no longer exists. Darhk learned that Project Genesis is doomed to die, and he along with it. And Malcolm Merlyn went from master of the League of Assassins to one-handed loner. Each villain failed, and only by banding together and defying the laws of time and space can they hope to snatch victory from the jaws of defeat.In many ways, the Legion aren't so different from the Legends themselves. Both groups are comprised of losers who need allies to accomplish a grand plan. The Legion are flawed and even relatable in a way we rarely see from Arrow-verse villains. Usually, there's a pretty straightforward formula with these shows. The villain is a dark mirror of the hero, one with a significant personal tie. Each season involves that villain executing a grand master plan to destroy either a city or the entire world, with the hero pushing themselves past their limits to save the day.But in this case, the Legion don't really fit that mold. Thawne doesn't want to rule the world; he just seeks the power to save himself from the zombie speedster that's been relentlessly hounding him. There's an urgency to his quest that makes him a compelling threat, but in a way that feels completely unique from his role in The Flash Season 1.We appreciate the attempts to think outside the box with this season's villains, and we're hopeful that will inspire the other Arrow-verse shows in their upcoming seasons. If nothing else, at least we know The Flash won't be battling an evil speedster for the fourth year in a row.In general, the Arrow-verse takes a pretty lighthearted approach to superhero storytelling, which is a major reason why fans love these shows so much. With these shows dabbling with everything from Gorilla City to Cyborg Superman in recent weeks, you could never accuse Greg Berlanti, Andrew Kreisberg and the rest of the gang from taking the DCU too seriously. These shows are simply fun to watch, and often it feels like the writers and actors are having just as much fun putting them together as viewers are watching the finished product.This year, though, Legends has really pulled ahead oft he pack when it comes to goofing around in the DC Universe toy box. So far this season, we've seen the team join forces with the Justice Society of America in World War II, get trapped in a trash compacter with a young George Lucas, and play cops and robbers with the Legion of Doom in Prohibition-era Chicago. Heck, the show even beat The Flash to the punch by having Professor Stein and Mick break out into an impromptu musical number. Even when the show gets dark (and things have gotten pretty grim at times this season), there's a lighthearted playfulness to Legends that never fails to elicit a smile.No other Arrow-verse show is quite so good at maintaining that balance between dark character drama and happy-go-lucky adventure. Supergirl is pretty good about that most weeks, but The Flash could definitely stand to lighten up. With so much emphasis on Barry's Flashpoint woes and too little on the simple thrill of the speedster lifestyle, The Flash needs to look to the example being set by Legends as it moves into Season 4.Arrow more or less gets a pass in this area, as that show has greatly improved its prospects this season precisely because it went darker rather than lighter. Still, even on a show like Arrow, there's only so much darkness and despair viewers can take before they need a change of pace. It doesn't hurt to take a step back every so often and remember how lovably ridiculous these costumed heroes truly are.

Jesse is a mild-mannered writer for IGN. Allow him to lend a machete to your intellectual thicket by following @jschedeen on Twitter , or Kicksplode on MyIGN