Sailor Moon is a classic magical girl tale about Sailor Senshi (Sailor Guardians) who come from outer space to Earth to fight for love and justice. It's a quintessential magical girl anime with a gang of female superheroes. It's often a fans' introduction to shojo stories, or anime in general.
One of the most enduring aspects of Sailor Moon, aside from its epic romance, is its main group of girl heroes. These heroes all have extensive personalities, talents, and superpowers. The number of them grows as the seasons continue on, but there are some amazing side characters who would also make interesting Sailor Guardians.
10 Naru Is Usagi's Best Friend
Naru Osaka is Usagi Tsukino's peer at her school, and her best friend. She gives Usagi good advice and loves her just as she is. Though she's a human with no powers, she could make a great Sailor Guardian. Naru is compassionate, enthusiastic and energetic, and she has a good heart.
Naru gets dragged into Sailor Guardian business a lot, though she doesn't really know what exactly is going on, because the Sailor Guardians need to keep their identities secret. If Naru is going to get targeted by the Dark Kingdom and other antagonists, she might as well become a Sailor Senshi.
9 Prince Demande Should Have Become an Ally
Prince Demande is a huge missed opportunity when it comes to his villain redemption arc. He starts out in Season 2 as a villainous general who works for the nefarious Wiseman. Wiseman warps Prince Demande's love for Sailor Moon into something dark, but Prince Demande shakes off Wiseman's control just in time to save Sailor Moon.
Just as Prince Demande finds his goodness again, Wiseman kills him. There are some Sailor Guardians who are men, like the Sailor Starlights, and Prince Demande would have made a great Sailor Starlight. It would have been a refreshing change for a villain redemption arc to turn into a Sailor Senshi awakening. Prince Demande has a great mind, heart, and powers that would aid the Guardians well long term.
8 Koan Matches the Senshi Style
Koan is an easy choice for an official Sailor Senshi because she's designed to be the evil version of Sailor Mars. Her personality and character design is different enough that she would add to the group well without being too repetitive. She even has her own power set with attacks like Dark Fire and Dark Power, which is a lightning-based attack.
Koan also knows the importance of sisterhood, like the rest of the Sailor Senshi. Sometimes she may fight with her fellow Spectre Sisters, but the Senshi are no strangers to occasional spats, either. Koan also has a great catlike hairstyle with odango, which is similar to Sailor Moon's, but also different enough because of her wavy texture and darker hair color.
7 Esmeraude Could Add Something New to the Senshi
The Senshi could always use more green-haired guardians. Esmeraude would not only add aesthetically to the Senshi, she has an engaging personality that would add well to their dynamic. Emeraude can also transform into a powerful dragon, which would be a refreshing new ability for the Senshi who could surely use an enchanted dragon ally.
Esmeraude would also get along well with Usagi, as they both enjoy feasting on sweets. Esmaraude always wanted to be a queen, and technically, the Senshi are princesses of their own planets. Esmeraude could surely name her own planet Emerald and would make an excellent Senshi and princess.
6 Phobos & Deimos Have Human Forms in the Manga & Sailor Moon Crystal
Phobos and Deimos are Sailor Mars' trusty crow friends, so technically, they are already allies to the Sailor Senshi. In the manga and in Sailor Moon Crystal, they have their own pixie-sized human transformations, and their red and dark purple-blue color scheme compliments Sailor Mars well. They would make great official Sailor Senshi, though.
Crow powers are something that's not really represented yet in the Sailor Senshi, so Phobos and Deimos would be great additions. In the manga, they served Sailor Mars as Princess of Mars, and on earth, they help her interpret her prophecies. It would have been great if that storyline was featured more, and expanded in the anime.
5 Countess Rose Has a Commanding Presence
One of the prettiest Sailor Moon villains is sadly in only one episode, "Let's Become a Princess: Usagi's Bizarre Training." Countess Rose works for the Dark Kingdom, and she runs a Princess Seminar. Obviously, the seminar isn't meant to teach manners, but to collect energy for Queen Beryl and Metalia.
Countess Rose is a beautiful woman, but a youma in disguise. Appropriately, her youma form is also gorgeous, and princess-like. She has blue-tinted skin and wears a mermaid-inspired gown with seashell adornments. There are already two Senshi with water-themed styles, Sailor Mercury and Sailor Neptune, but Sailor Mercury's water powers are ice-based and Sailor Neptune's powers are more like a sea god's Countess Rose could have a very pretty mermaid theme as a Sailor Senshi.
4 Queen Serenity Could Fight Alongside Her Daughter & Granddaughter
The two most recently-born girls in the Moon Kingdom line are Sailor Senshi, Sailor Moon and Sailor Chibi Moon. If Princess Serenity and her future daughter and crown princess are Sailor Senshi, it would stand to reason that Serenity's mother, Queen Serenity would also make a great Sailor Senshi if she survived the Moon Kingdom destruction. The former Queen Serenity has key leadership skills, and has all the virtues that go along with being a Senshi.
It takes a lot of bravery and self-sacrifice to fight for love and justice along with the rest of the Senshi. Queen Serenity demonstrated compassion, sacrifice, bravery, and quick thinking in a crisis so well that she served as a foundational influence on Sailor Moon. Since she has lavender hair and a silvery gown, her Sailor Senshi uniform could be silver and lavender, which is an underutilized color scheme in the canon Senshi.
3 Princess Kakyuu Has Untapped Potential
Princess Kakyuu inspires such loyalty in her subjects that the Sailor Starlights devote their lives to finding her after their kingdom's destroyed. The Sailor Starlights describe her as a worthy and compassionate leader. She also has healing powers that would rival Sailor Moon's.
Unfortunately, Princess Kakyuu dies before she can show any of her legendary powers. Sailor Moon revives Princess Kakyuu, but she doesn't have much influence on the plot after her death and revival. If she became one of the Sailor Senshi and restored her planet, she would have amazing powers to aid Sailor Moon's and could be more involved in the central story line.
2 Thetis Deserved More Than One Episode
Thetis is a youma (demon) woman who works for the Dark Kingdom. She's a water elemental demon and one of Queen Beryl's favored youma who also worked with Jadeite. Queen Beryl hates that she was killed off so quickly by Sailor Moon's Moon Tiara Action attack, because she had so much potential.
Thetis could have fulfilled her missed potential by switching sides and being the fourth Sailor Senshi to join Sailor Moon. Thetis has a gorgeous human form with dark sapphire hair, excellent plotting skills, and a great water-based transformation. She may be evil but with a magical transformation like hers, she would have made a great Senshi.
1 Fiore Deserved More
Fiore comes from a destroyed planet, and he wanders the universe lost and alone. He befriended Mamoru as a young child. Mamoru fights alongside the Sailor Senshi partly because he yearns for the family that he never had as a young child. Fiore could satisfy his natural wish for community by joining the Sailor Senshi rather than aligning himself with the evil flower alien, Kisenian.
It seems that Fiore (whose name means "flower" in Italian) comes from the same planet as Ail and An who serve the Makai Tree, so it stands to reason that he would retain some planet powers without serving as Kisenian's host. Sailor Jupiter also has plant powers, and Fiore would make a great ally to her and the rest of the Senshi as a fellow guardian.
