With the Magic Knight Rayearth remake looming ominously in the promise of a 2026 release, there's something else I wanna say before the new anime is released and the tag is flooded with a bunch of newbies who are afraid of spoilers and people who have no media literacy.
Zagato's main motivation for what he did was not simply that he was in love with Emeraude. That was no doubt a huge factor in his motives, but is absolutely not the main one. I know this. I know it because he explains his motives quite clearly in the final battle. Hikaru, Umi, Fuu, and Princess Emeraude herself just didn't understand it until it was too late.
What's his main motivation?
Well, I'm too lazy to go grab screencaps, but my 20 year old copies of the manga are right here. I don't have a fancy scanner so you'll just have to bear with me and my shitty phone camera.
When asked why he kidnapped Emeraude and is letting Cephiro crumble, Zagato doesn't say "I'm in love with her and want her to myself." That would be way too easy of an answer and would not do justice to his character, or the story. Instead Zagato talks about how the Pillar is bound to pray only for Cephiro, that Princess Emeraude has no freedom and is not allowed to pray for anything else that she might desire.
Hikaru, Umi, and Fuu are actually justifiably confused by this. Their entire journey to this point has been full of people telling them that Zagato is the bad guy who imprisoned Emeraude against her will. Yet here he is, speaking only about Emeraude's freedom and well being. Of course they are confused, this does not align with what they have been told, and believe so strongly that they are willing to kill him over it.
Princess Emeraude was confused for a long time too. She directly asked him why he's doing this and if he cares at all about Cephiro. In the anime Zagato explicitly says no, he doesn't care what happens to Cephiro, but in the manga he doesn't answer her at all when she asks. Emeraude only vaguely gets an answer much closer to the climax when Zagato says this
It's soooo easy to read this as Zagato confessing his feelings for Emeraude, but this scene is so much more than that. This is Zagato showing his resolve. This is him telling her that no matter what happens, he will not back down, or change his mind about his motives. Motives that Emeraude does not fully understand until his dying words.
Not "I love you." Not "Be mine".
This whole time, Zagato's motive has been to show everyone that the Pillar system is wrong, that Emeraude should not have to die just because she is not an infallible goddess. And the thing is, he doesn't have to be in love with Emeraude to think that way. The narrative does go on to show that Zagato does in fact reciprocate Emeraude's feelings for him, but that was never what he himself said and not at any point were those feelings his sole motive.
Emeraude has been conditioned her whole life to believe that she must pray for Cephiro's prosperity and only Cephiro's prosperity. Pretty much every person in Cephiro has also been conditioned to believe that Emeraude is some sort of goddess, perfect and untouchable. Zagato is the only one at this point of the story who saw Emeraude as a human being, a person with feelings and rights that should be valued.
And this may very well be why she fell in love with him in the first place. Also why she is so confused by his motives.
The man she loves because he sees her as a person and values her wants and her desires is suddenly acting completely out of character by disregarding her pleas to let the Magic Knights do what they were summoned to do and save Cephiro; why? Why is Zagato doing this? Because he knows that she is a human being who deserves to live and love with her whole heart and he disagrees with the system that says she has to die for failing to be a perfect goddess.
I like to imagine that if Hikaru, Umi and Fuu had understood what Zagato was saying in that final battle, both he and Emeraude could have been saved. Or if Zagato had made contact with the girls before Clef could tell them the story about how Emeraude had been kidnapped and that they had to save her. Hell, even if he had just said "I'm in love with her" at any point, a lot of pain could have been spared.
But alas, being in love with Emeraude was not the point that Zagato was trying to make. He needed everyone to know that Emeraude was a human being, not an infallible goddess, and that the system that treated her like one and kept her bound to a fate that said she had to die if she failed was wrong. The fact that no one listened to him or understood what he was saying until it was too late is the biggest tragedy for his role in the story.
If there is one thing I want from the upcoming remake, it's for more acknowledgement that Zagato was right. Even if his methods were cruel, he was the first one to stand up and say that this "system is wrong" and try to fight it and I don't think he gets enough credit for that. Most of the time when Zagato is brought up after his death, it's only in the context of him and Emeraude being in love, and that does quite a bit of disservice to his character.