Many Sailor Moon characters die and are revived or reborn, but many don't come back after they die, especially the villains and henchmen. But though they work for the darker forces of the universe, they tend to be complicated characters capable of true redemption. Some are even working for the baddies under duress or because they've been brainwashed.
Other characters have been good people consistently from the very start and met tragic ends, never to return. While high stakes and consequences are important in storytelling, those consequences don't have to mean certain death. These promising characters deserve to come back and play a further role in the Sailor Moon 'verse.
10 Queen Beryl
Queen Beryl is a fierce sorceress and servant of Queen Metallia. The '90s Sailor Moon anime especially paints her as a flat character driven by greed. She covets energy and power, and she covets Endymion (now Tuxedo Mask).
The original manga and Sailor Moon Crystal shed more light on Queen Beryl's complexity. While her unrequited love doesn't entitle her to much sympathy at all, her manipulation by a force much larger than her does. In the manga, Beryl wrestles with self-loathing and believes she's beyond redemption. It would be interesting to see a Beryl come back with a more enlightened view of herself — maybe she could turn her immense sorceress powers for good.
9 Rubeus
Rubeus is the leader of the Black Moon Clan, puppeteered by Wiseman. Rubeus isn't the most sympathetic of the Sailor Moon villains, but he has really cool powers and an amazing character design. He's like the gender-bent version of Sailor Mars, with his hair like a tuft of flame and impeccable 1990s streetwear.
Rubeus deserves to come back, if only to serve more fashion looks. He's the first villain of the Black Moon Clan to die, but he could have used more time to wreak havoc.
8 Saphir
Wiseman is one of the creepiest, most nefarious antagonists in Sailor Moon, second perhaps only to Chaos itself. Saphir is rightfully dubious about Wiseman, and when he uncovers Wiseman's machinations, he tries to warn Demande.
Saphir barely escapes Wiseman, but he's injured. Ultimately, Saphir doesn't survive Wiseman. Not only is Saphir a smart character willing to question an evil lord, but he also looked out for others, and he has a tragically star-crossed romance. The depiction of Petz's grief over his loss set to the Moonlight Densetsu Locket Theme is heartbreaking; they deserve another chance to be together.
7 Jadeite
Jadeite gets the most screentime out of the Dark Kingdom generals in the '90s anime, so it's a blow when Queen Beryl kills him as punishment for failing his mission. In the manga, he's finished off by Sailor Mars.
Jadeite is a purely fun villain. He's scrappy, sassy, stubborn, and powerful. He knows how to delegate, but he also isn't afraid of getting his hands dirty. He was once a good person, and it would be great to see what he was like when he served the Prince of Earth with that same scrappy personality.
6 Zoisite
Zoisite is the prettiest Dark Kingdom general. He's incredibly elegant and has excellent, shojo-worthy transportation sequences — he teleports from place to place in a small windstorm of pink petals. He doesn't bother with civilian disguises like Nephrite and Jadeite love to do; he's fine just as he is. Zoisite also has a sweet romance with another Dark Kingdom general, Kunzite.
Zoisite deserves to come back just to be with Kunzite because their romance is so sweet and believable. His death was truly tragic and one of the first times fans shed a tear for an antagonist.
5 Kunzite
As the most powerful agent of the Dark Kingdom, Kunzite is a fierce antagonist for the Senshi. There's something about villains with frighteningly vast powers and big hearts that will always stick out to fans.
Kunzite may be ruthless when it comes to serving the Dark Kingdom, but he will give everything up to help the love of his life. In his previous life, before he was taken and brainwashed by Metallia, he served Prince Endymion as the leader of his Heavenly Kings, dubbed the Knight of Purity and Affection. That part of his former life shows how much he loves Zoisite. He's too wonderful of a character to die in his second life and never be reincarnated again.
4 Nephrite
Not only were the four Dark Kingdom generals Prince Endymion's Shitennou in their previous lives, the manga and Sailor Moon Crystal note that the Knights had romances with the Inner Senshi. In that previous life, Nephrite had a relationship with Sailor Jupiter.
Before Zoisite's youma finished him off, Nephrite studied the stars and harnessed their gifts for his powers. He also had excellent personal style and a romance with Naru. It would be even more compelling if such an interesting character could come back to reassume his romance with Sailor Jupiter.
3 Prince Demande
Prince Demande is a fun antagonist because he's meant to be Prince Endymion's foil. He terrifies Sailor Moon and has unrequited love for her, though thankfully, Tuxedo Mask steps in and stops Demande from menacing her.
Once more, Wiseman is the culprit behind such villainous misdeeds. He pulls Demande's puppet strings, and to his credit, Demande actively tries to resist and eventually shakes Wiseman's hold. Demande dies saving Sailor Moon from Wiseman, but so much more could have been done with his character. It would have been fun to see more of Tuxedo Mask's sassy prince foil, free of Wiseman's hold.
2 Fiore
Fiore is such a sad antagonist. Like Sailor Galaxia, he was in the wrong place at the wrong time, taken advantage of by an Eldritch horror in space. The Kisenian blossom uses him to hurt Sailor Moon, warping his reasoning and giving him the false promise that he'll get Endymion back.
Fiore shakes the Kisenian blossom's hold, and Fiore more than makes up for his misdeeds. He gives his life force to revive poor Sailor Moon. All Fiore wanted was to not be alone anymore. He deserves a happier ending — and to see Endymion again.
1 Queen Serenity
Queen Serenity is the ultimate good; she's by no means a villain. But she is dead from the start with no chance of ever coming back. She communicates with her reborn daughter via hologram on the ruins of the Moon Kingdom, which is both unearthly sad and sweet.
Sailor Moon is so close and yet so far from the mother that sacrificed herself to save her. There's no thematic reason to bring Queen Serenity back, but Sailor Moon deserves a mother's hug after all the sacrifices she's made for the universe.