DC superheroes have a thing for hiding their identities (Wonder Woman, Batman, Superman — you get the picture), and this includes Supergirl, i.e. Kara Zor-El/Danvers. In Supergirl, Kara hides her superhero persona by wearing glasses, pretending to be ditzy and shy, and obviously hides her costume underneath her many button-ups. But of course Cat Grant knows Kara's secret, and it makes us wonder who else knows Kara's true identity.Who knows Supergirl's identity?These are the people who know Supergirl's real identity: Family members like Superman, Alex, Eliza, and Jeremiah; friends like James Olsen, Winn, J’onn, Mon’El and Cat; acquaintances like Lucy Lane and Maggie Sawyer; and unfortunately several enemies. This includes Maxwell Lord, Lillian Luthor, Rick Malverne, Thomas Coville, Music Meister, and Mr. Mxyzptlk. Oh, and Lena Luthor.This is definitely not the full list, but it's large enough to make people wonder if Kara is even trying to hide her identity anymore.It's actually a pretty long list of people who know Supergirl. But one Reddit user pointed out that it just may be hard to maintain the secret, storyline-wise. "It seems superhero shows love to have secret identities only to reveal them immediately to as many people as possible and somehow.. it's a secret.. sighs. I thought after they did that with Arrow they wouldn't in Flash but they did the same thing, and the same thing again in Supergirl," they wrote.Another replied, "Yes, I think it's hard to maintain."While this was posted in 2017, this video completion of all the characters who know Kara's real identity shows that there are a LOT of them.But then we learned in Season 5, Episode 13, what would happen if Supergirl revealed her superhero identity. (Hint: Nothing good.)In the episode, Mr. Mxyzptlk gives her the opportunity to go back in time and unveil her true self to Lena, and he showed her several scenarios that depict what would happen. The consequences worsen and worsen, including all of her friends being killed.Most recently, Supergirl's identity reveal happened off screen. Supergirl showrunners Jessica Queller and Rober Rovner opened up to The Wrap about why Alex told Kelly about Kara being Supergirl off screen. “It was something that we had toyed about being able to do at the end of the first episode, but the story kind of — we didn’t have the time in that episode to achieve that."They added, "Because Kelly was fine with the news, we felt that we could integrate it into the story and that their relationship — it was something that Kelly was going to be very supportive [of] and helping Alex cope with this. And some of it is explored in the next episode, when Alex is having a very difficult time."Should Supergirl come clean to everyone before the show ends? We'll just have to keep watching to see what happens. \n\nWatch Supergirl every Tuesday night at 9 p.m. EST on the CW.