Well, this particular reference I can't take credit for, I saw it on Reddit (I think) so I'm pretty much just the messenger, spreading the information around! We probably shouldn't hope to see any member of the Royal Family in the episode since they're being saved for the movie, but it was around the filming of this episode that Constance Zimmer was interviewed by Yahoo and dropped this intriguing bit: “Somebody just found out the other day that they were something that they had no idea they were. All of us were shocked and I imagine, for that person, they’re like, 'Wait a minute. So that means that everything up until now has been a lie!’ It’s so fun to live in that world of mystery — as the Marvel world should be!” Source: https://www.yahoo.com/tv/agents-of-shield-which-cast-member-is-164151700.html Yeah, I checked a lot the Secret Warrior profiles in Marvel's wikia during the hiatus and recently bought and read all six trade paperbacks of the Secret Warriors comic book, so now I know quite a bit about them. The paperbacks were an amazing read, so cool to see how much it inspired the MCU: the three new generation helicarriers, HYDRA's infiltration in SHIELD, Sandbox and Providence as SHIELD bases, the list goes on!