Voltron: Defender of the Universe, in syndication
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This first aired in 1984-85. It holds a fond place in my heart for being probably the first thing I ever saw which could be called anime. (Also, there were some cool toys based on the show, of which I had a few, though sadly I don't still have them.) But actually, "Voltron" only used visuals from the anime "Beast King GoLion" (for season one), and from the unrelated anime "Armored Fleet Dairugger XV" (for season two). But I know nothing about the plots of either of those series. It was an American company that created their own story and dialog to go along with the visuals, rather than simply translating the original series into English. But I didn't know about any of that until many years after I originally watched the show, as a kid. And by the time I wrote my initial review of the show (probably in the early 2000s), I didn't remember a lot of details. But I'm rewatching it on DVD, starting in 2016, and as I do so, I'll update my review. (I gotta say, there are a lot of things that make no sense to me now, like the fact that the words "solar system", "galaxy", and "universe" are sometimes used interchangeably. And the stock footage of things that happen the same way in most episodes isn't changed when the way they happen changes in occasional episodes. And... I could go on and on, but it's not important.)
Season One: Defender of the Far Universe (aka "Lion Force Voltron")
So, Voltron was this giant robot that fought evil and stuff. But then one day a witch named Haggar cast a spell that broke Voltron up into five separate robot lions, which crashed on planet Arus. Haggar works for an evil king named Zarkon, who now invades Arus. So the Galaxy Alliance (which is headquartered at Galaxy Garrison, on Earth) sends five pilots (Keith, Lance, Sven, Pidge, and Hunk) to Arus. But they're captured by Zarkon's forces and sent to Planet Doom (the ruling planet of Zarkon's empire). They escape in episode 2, and return to Arus. There they meet the beautiful Princess Allura and her adviser, Coran. Allura wants to protect the people of her planet from Zarkon's forces, a task that has fallen on her since the death of her father, King Alfor. (Though Alfor still occasionally appears to her as like a hologram or something, to advise her.) And now the five pilots move into the Castle of Lions with Allura and Coran, but they still have to find the hidden lions and reactivate them. The lions are fairly decent fighting machines individually, which they use against most of Zarkon's forces (which are commanded by General Yurak at the start of the series, but I had forgotten about him until watching the DVDs). But Haggar creates Robeasts, which an energy beam from Yurak's command ship makes grow into enormous monsters, against which the lions are pretty useless. So, the team combines them to form Voltron, against which the Robeasts are pretty useless.
It's kind of weird how some things happen a lot earlier in the series than I remembered, and some happen later. It isn't until episode 4 that they finally form Voltron for the first time. Also I need to mention that there are some space mice that Allura is friends with, who live with her in the castle; the mice don't talk, or anything, but they can be helpful, sometimes. (Pidge tries to make friends with them, too.) It's also in episode 4 that we see Allura have a flashback that includes the mice doing the Can-Can, which was one of the things I remembered best from watching the show as a kid, but I thought it must have happened later in the series. Another thing that I thought happened much later turns out to happen in episode 5. (I won't say exactly what that was, but it involves the Castle of Lions itself.) In episode 6, Sven is badly wounded by Haggar, and has to leave Arrus to get medical treatment. Without him, the Voltron Force can't form Voltron. I had actually thought that happened earlier in the series. Anyway, in the next episode, Allura begins piloting the Blue Lion. (Which forms one of Voltron's feet and legs. The other foot and leg is formed by the Yellow Lion, which is piloted by Hunk. Lance pilots the Red Lion and Pidge the Green Lion, which form the two hands and arms. Keith, the leader of the Voltron Force, pilots the Black Lion, which forms the head and body of Voltron. Although I have always thought it's weird that in the stock footage of the lions forming Voltron, Keith always says "Form feet and legs; form arms and body; and I'll form the head," even though his lion is the body and the head. Incidentally, I also feel like I can recall that standard dialog saying "torso" rather than "body," but either I'm just mistaken, or maybe it will change later in the series. We'll see.) It's also in episode 7 that Allura's old nanny (who is just called "Nanny") returns to the castle. (She doesn't get along very well with the Voltron Force, and wishes Allura wouldn't pilot the Blue Lion, because it's so dangerous.) And I believe this is the first time we hear Haggar call her pet cat by name: Cova. (Though we'll rarely if ever hear the name again. Usually it's just called "Kitty" or "Haggar's cat.")
In episode 14 (which apparently aired before episode 12), Zarkon gets tired of Yurak's constant failure to defeat Voltron. From this point on, Zarkon's forces will be led by his own son, Prince Lotor. (I remembered him as having always been the main adversary, before watching the DVDs.) And he has a rather creepy interest in Allura. And... I'll say more as I watch more of the series.
Season Two: Defender of the Near Universe (aka "Vehicle Force Voltron")
I don't think I saw much of this, so I never remembered it nearly as well as I did the Lion Voltron. But I believe it was set at Galaxy Garrison, and featured a different Voltron which was made up of a whole bunch of vehicles, so many that they were in individual units which could combine to form their own bigger... things... in addition to all the units coming together to form Voltron. Anyway, I certainly hope to see this season on DVD someday, so I can write a proper review of it.
In 1998-2000, there was a CGI sequel to the original series, called Voltron: The Third Dimension (which, like the original, was syndicated). I never saw it, so I couldn't say anything about it. In 2011-12, there was another series called Voltron Force (on Nicktoons), which I also never saw. And in 2016, there's a new series on Netflix, called Voltron: Legendary Defender, which I don't have the option of seeing, since I don't have Netflix. But I'm sure none of these series would be as important to me as the original, anyway.