To many, as far as the quality of the content and the strength of its characters are concerned, the Arrowverse has been more successful than Warner Bros.’ DCEU. The CW’s expansive superhero franchise didn’t get to where it is without a few growing pains along way. Interestingly, some pains were inflicted by the very folks responsible for the source material the Arrowverse brings to the small screen. Fans need only recall the loss of the Suicide Squad in Arrow’s second season, which some contend set the series off course a bit, to see evidence of the ongoing push and pull. Apparently, there are, understandably, rules in need of following when it comes to the development of the shows.

As Arrowverse executives often remind curious fans, they’re merely “borrowing” DC characters. What one borrows can be effectively taken back upon the owner's request. And borrowing is the very foundation upon which The CW franchise is built. However, it’s been known to not always act in everyone’s favor. The DCEU has claim of certain characters that the Arrowverse is not, or is no longer, allowed to feature. The list below notes 15 questionable restrictions regarding Arrow, The Flash, Supergirl and Legends of Tomorrow.

15 THE SUICIDE SQUAD IS OFF-LIMITS

Arrow's Suicide Squad

One of the Arrowverse’s more compelling storylines involves Task Force X. During Arrow’s sophomore season, Amanda Waller assembles a team of supervillains to carry out a deadly mission. Debuting the first live action Suicide Squad meant Arrow had a high bar to set. Fortunately, the series set it well. Unfortunately, the possibilities were halted; thus, the Squad didn’t get to live up to its fullest potential.

With the development of a theatrical Suicide Squad came news of Arrow’s having to ditch its own plans.

What’s odd is that as the show dismantled its version of the villainous team, another two years passed before these characters hit theaters. This is especially perplexing when we consider The Flash premiering days after the character’s announced to appear in the DCEU. If these decisions are made on a character-by-character basis, what makes some more eligible than others to feature in two franchises at once?

14 NAME-DROPPING BATMAN SEEMS FORBIDDEN

Batman and Superman

Batman is confirmed to exist on at least two Earths in the Arrowverse -- Earth-1 and Supergirl’s Earth-38. The confirmations are never explicit, though. Superman having worked with a “brooding” vigilante and Oliver’s announcement that the title of Oracle is taken supplies plenty of implicit evidence. Yet, Batman himself has never been name-dropped, and, no, the recent Bruce Wayne nod doesn’t count.

With the debut of Superman in Supergirl’s second season premiere, confusion only doubled. Why is the Man of Steel allowed to feature in two different live action universes like The Flash? The general consensus posits the reasoning rests on money and/or legalities. Fox does own the television rights to the Dark Knight, after all. But, again, Bruce Wayne’s recent mention on Arrow leaves us collectively scratching our heads.

13 MIXED-MESSAGING ABOUT DEATHSTROKE

Manu Bennett's Deathstroke in the Arrowverse

Arrow’s Deathstroke will be remembered beyond his time as one of the Arrowverse’s greatest villains. The reformed and troubled mercenary may go down as one of the better developed antagonists in genre television. However, there’s constantly trouble marring fans’ enjoyment of the Terminator.

More so than any other shared Arrowverse/DCEU character, the rules governing Deathstroke’s usage seem arbitrary.

After being locked away on Lian Yu in Arrow’s second season, Slade makes some unfavorable appearances in season three. Apparently, Arrowverse executives were told the mercenary was off-limits. Of course, his then hopeful appearance in the DCEU benched him on television. The fifth season sees him return in grand fashion and the show’s sixth run couldn’t have provided him a better send off. Again, thanks to big screen plans, Deathstroke is officially benched again on television. Unfortunately, the perplexing back and forth will probably never receive a genuine explanation.

12 DEADSHOT HAD TO BE KILLED OFF

Michael Rowe as Deadshot

Deadshot’s featured in less than a dozen episodes, but his time on the series is as memorable as any. Given a redemption arc courtesy of his recruitment into the Suicide Squad, the character’s story at least concludes in an appreciated manner. Floyd Lawton is seen twice more after his death in Arrow season three. His first post-death appearance is on The Flash’s Earth-2 episode, where Lawton is a meek detective and a terrible shot. Lastly, he pops up during Arrow’s fifth season, acting as an imprisoned Diggle’s subconscious.

Like others, his Arrowverse departure coincides with production of the live action Suicide Squad film. It’s hard to imagine the logistics behind what fuels such decisions. Yet, we’re left to wonder why he was killed off. Could he have received the Deathstroke treatment, allowing him to feature on television as the films permitted? An answer may never be given.

11 GREEN LANTERN IS OFF-LIMITS

Green Lantern

This, admittedly, isn’t an egregious example of seemingly arbitrary rules governing character use in the Arrowverse. Green Lantern has been implicitly referenced a number of times; Hal Jordan himself has even been indirectly mentioned on The Flash. But there is no evidence of the Arrowverse ever taking strides to procure him for a storyline.

In essence, the Lanterns are just one of those things that’s strictly off-limits, presumably never to be touched on The CW’s superhero slate.

As the series of shows have yet to deeply delve into the cosmic side of the DC Universe, his lacking a presence isn’t exactly felt. But because the Lanterns often act as a launching pad for DC’s cosmic-centric adventures, it’s a shame they will continuously go unexplored in the Arrowverse. This is especially unfortunate considering Green Lantern’s currently sitting on the sidelines in the DCEU.

10 AMANDA WALLER HAD TO BE KILLED OFF

Amanda Waller on Arrow

Once the Suicide Squad made its swift exit from the Arrowverse, Amanda Waller was set to follow soon thereafter. Killed during Arrow’s fourth run, the A.R.G.U.S director’s departure is still considered a strange move by many. Did the Suicide Squad film have to entail the murder of television’s Amanda Waller? Couldn’t she have been required to go into hiding, or coerced to step down from her position?

The more important question to ask is why A.R.G.U.S, also a major entity in the DCEU, is not yet defunct in the Arrowverse. Evidently, the rules apply to teams and individuals; government organizations need not be concerned. This is yet another aspect of the ins-and-outs concerning the Arrowverse and DCEU that will likely never receive clarification.

9 THE MINIMAL USE OF SUPERMAN

Tyler Hoechlin's Superman

National City can’t go through a crisis without fans pondering why Superman isn’t lending Supergirl and the DEO a hand. The short answer seems to always point toward the fact that the Arrowverse is merely borrowing characters from DC. From the little that’s been seen of him, audiences are attached to Tyler Hoechlin’s Man of Steel.

However, it appears as though Supergirl will continue its minimal use of him for the foreseeable future.

Akin to other characters similarly caught between the television universe and the DCEU, the anomaly that is The Flash remains point of reference when questioning Superman's TV and film status. To the dismay of many, no explanation has been given as to why what works for the Scarlet Speedster can’t work for anyone else. Some speculate it’s about popularity, but characters like Deathstroke and Deadshot nullify such arguments.

8 WONDER WOMAN MAY NEVER APPEAR

Themyscira on Legends of Tomorrow

Recent discussions of characters the Arrowverse cannot explore confirm the Amazonian may never appear on The CW shows. The news isn’t surprising, but some semblance of hope was raised early in Legends of Tomorrow season three. As the newest Legend, Zari, returns Helen of Troy to her proper place in time, she drops Helen off on land that isn’t Troy. Helen is instead taken to “an island full of warrior women.” Without disrupting the timeline, Helen of Troy lands on Themyscira. The easter egg confirms the existence of the Amazons and, by proxy, Wonder Woman.

Sadly, that’s all fans will probably get of the character, aside from more subtle hints and teases. To reiterate, Wonder Woman being off-limits shocks no one. Yet, it’s another example of the nebulous rules the shows must adhere to, leaving some to ponder what’ll happen once The Flash’s solo film finally hits theaters.

7 THE AXING OF ARROW'S HARLEY QUINN PLANS

Harley Quinn on Arrow

It’s no secret Arrow had more in store for Harley Quinn than what’s on display in season two. As the story goes, once Suicide Squad picked up steam, Harley and the Task Force were suddenly no longer in play for the Arrowverse. Some fans still lament this decision, while others have since moved on. However, few will argue against the notion that, to a degree, these rules often stifle creativity.

Also disappointing with regards to Harley, is that her backstory will never receive exploration.

Are her origins of their traditional make, or did Arrow change things? Of additional interest is that she’s still alive. Unlike Deadshot and Amanda Waller, Harley was only indefinitely benched. Thus, that detail may leave room for her to return in some capacity. With the myriad projects the character’s purportedly attached to in the DCEU, those hopes are probably better left cast aside.

6 JUSTICE LEAGUE?

Crisis on Earth-X Arrowverse Heroes Together

Since the Hall of Justice was so blatantly teased during the "Invasion!" crossover, fans have awaited an official team name for the Arrowverse heroes. The most recent crossover, "Crisis on Earth-X", is sans both the Hall and a title for the group. How has Cisco yet to even cursorily discuss what their name should be? How has no one prompted him to workshop something? It’s puzzling, to say the least.

The reasoning could be that Justice League is absolutely off the table. Yet, Justice Society, a name Amaya and the Legends would have no problem proposing, hasn’t been co-opted either. Since all traces of the Suicide Squad have been nixed from the Arrowverse, it stands to reason that anything with “Justice” in the title can’t be utilized.

5 CHARACTERS SPOKEN FOR ELSEWHERE ARE OFF THE TABLE

It has recently been made abundantly clear that characters appearing in other live action films or television shows are off the table. As such, this seemingly puts the nail in the coffin on dreams of ever seeing Dick Grayson/Nightwing (or Hawk and Dove) appear in the Arrowverse. This stipulation also undoubtedly extends to other Teen Titans that are to appear on DC’s impending Titans television series.

Whether or not the villains seen in Titans will be allowed to co-exist in two different universes remains to be seen.

Antagonists such as the Dollmaker and Ra’s al Ghul featuring on both Gotham and Arrow just years apart further complicate the messaging. At least the subtle hints and cleverly placed easter eggs are unlikely to go anywhere. It’s just a shame nothing can ever be made of them.

4 CITY LIMITS

Metropolis on The CW's Supergirl

Years ago, as the Arrowverse’s first crossover between Arrow and The Flash was rolling out, the names of famous DC cities were off-limits. At the time, Arrowverse producers were citing Gotham and Metropolis as an example. Of course, this has since changed with the advent of Supergirl, where Metropolis is seen on-screen and Gotham has been name-checked.

If the homes of the Man of Steel and Dark Knight are now game on the small screen, it stands to reason other locales are also free from limitation. Still, the used-to-be stipulation is worth noting as an oddity. This particular mention also serves as acknowledgement of how far things have come in such a short period of time. DC and Warner Bros. have loosened the reins, and, thus far, it’s been for the better. Who’s to say they won’t loosen some more?

3 INTERESTING DETAILS LEFT UNEXPLAINED

Arrowverse Deaths Felicity Smoak

Lacking direct mentions of Batman and the diminishing chances of ever seeing any Teen Titans aren’t the only Bat-related limitations imposed on the Arrowverse. There are hints suggesting the rest of the Bat-family are under similar restrictions. This specifically relates to Barbara Gordon/Oracle, who apparently exists in the Arrowverse.

She’s indirectly referenced by Oliver, when he deems Felicity Overwatch and states that the Oracle moniker is already taken.

It’s doubtful anyone expects to ever see Babs appear on any of the shows. However, what’s odd are the questions her existence raises. Chief among such curiosities are how Oliver knows about her. Does his knowledge somehow connect to his past stewardship under Talia al Ghul? Sadly, what he’s been made privy to and how seems as though they, too, are likely to remain left to the audience’s imagination.

2 LEX LUTHOR IS NAME-DROPPED, BUT NEVER SEEN

Jesse Eisenberg's Lex Luthor

Apart from a Supergirl flashback featuring young Lex Luthor, the Superman villain has yet to properly grace the Arrowverse with his presence. Of course, the Luthor of focus at present, and into the foreseeable future, is Lex’s sister, Lena. However, with Lex’s consistently being mentioned, and his and Superman’s tumultuous relationship always receiving reference, it is a bit odd that he hasn’t been seen yet.

Based on precedence, it stands to reason his absence is explained by the character’s role in the DCEU. If Justice League’s second post-credit scene is anything to go by, his big screen presence will soon increase ten-fold. Taking this into account, Lex Luthor’s future in the Arrowverse, should Supergirl choose to explore it, may be limited if not all together non-existent.

1 NO RESTRICTIONS ON THE FLASH

Grant Gustin as The Flash

One aspect of the Arrowverse that's continuously bewildering, considering the apparent dos and dont’s, is The Flash. But it’s not just the Speedster himself that appears to be the anomaly; his rogues gallery and most famous storylines, i.e., "Flashpoint", are also strangely explored in full on television.

Amidst all the rumors about the character’s solo film being packed with villains, the show never slowed down on its casting of famous Flash foes.

Additionally, San Diego Comic-Con 2017 marked the second year in a row where "Flashpoint" was the talk of the town, as it had been in 2016 with news of the show’s third season. So what’s protecting the Scarlet Speedster that isn’t applicable to the rest of the Arrowverse? Perhaps he lucked out, having a show dedicated to him prior to the DCEU properly kicking off.