The Senshi Registry

REGISTRY OF THE SILVER MILLENNIUM Department of Planetary Guardian Assignment

Every Sailor Senshi is bound to a celestial body — a planet, moon, asteroid, or star — and that binding determines everything: powers, colors, personality, transformation phrase, attack names, and role within the Senshi hierarchy. This registry guides you through selecting and developing your Senshi identity from celestial assignment to final costume design.

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Celestial Body Selection

The inner and outer planets of our solar system are taken by canon Senshi. But the cosmos is vast. Here are the available celestial categories for OC Senshi, ranked by narrative potential:

Tier 1 — Dwarf Planets and Major Moons (Highest Potential)

These bodies have established mythology and enough scientific character to build a full Senshi identity around.

Celestial Body	Mythological Source	Power Theme Suggestion	Color Palette
Ceres	Roman goddess of harvest and agriculture	Growth, decay, natural cycles	Gold, wheat, forest green
Eris	Greek goddess of discord and strife	Chaos, disruption, truth revealed through conflict	Dark purple, electric pink, black
Haumea	Hawaiian goddess of fertility and childbirth	Creation, transformation, new beginnings	Ocean blue, coral, white
Makemake	Rapa Nui creator deity	Primordial power, bird motifs, isolation	Earth red, volcanic grey, sky blue
Sedna	Inuit goddess of the sea and marine animals	Deep water, cold depths, exile	Arctic blue, silver, deep navy
Charon	Ferryman of the dead (Pluto's moon)	Passage, boundaries, the space between life and death	Charcoal, pale silver, ghostly blue
Titan	Saturn's largest moon; named for the Titans of Greek myth	Ancient power, fog/atmosphere, hidden strength	Orange-gold, deep amber, haze grey
Europa	Zeus's lover in Greek myth; Jupiter's icy moon	Hidden oceans, secrets beneath surfaces, ice	Ice white, deep blue, cracked silver
Ganymede	Cupbearer to the gods; largest moon in the solar system	Service, grandeur, gravitational pull	Royal purple, bronze, cream
Io	Priestess of Hera; Jupiter's volcanic moon	Volcanic fury, passionate intensity, sulfuric beauty	Sulfur yellow, lava red, mottled orange

Tier 2 — Asteroids and Minor Bodies

Smaller bodies mean more niche powers and more creative freedom, but less inherent gravitas. These Senshi would be specialists rather than powerhouses.

Tier 3 — Stars and Constellations

The Sailor Starlights in canon are star-based Senshi from outside the solar system. An OC Senshi tied to a specific star (Sirius, Polaris, Vega, Betelgeuse) opens up cosmic-scale stories but places your character outside the solar system's Senshi hierarchy entirely.

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Dual Power Theme Architecture

Every canon Senshi operates on two interlocking themes: the mythological and the physical. Your OC needs both.

Sailor Mars — Mythology: war, passion, fire (Ares/Mars). Physical: literal fire, heat, flame divination. Both reinforce each other.

Sailor Neptune — Mythology: the ocean, art, intuition (Poseidon/Neptune). Physical: tidal waves, deep pressure, mirror-based precognition. The mythology adds depth to the physics.

For your OC, pair them:

Celestial body: Io

• Mythological theme: Hera's jealousy, transformation as punishment, priestess becoming something else
• Physical theme: Volcanic eruption, sulfuric chemical reactions, tectonic instability
• Combined identity: A Senshi whose power is volatile transformation — she doesn't just attack, she changes the battlefield's chemical composition. Her backstory involves an identity forced upon her, which she's learning to claim as her own.

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Transformation Sequence Design

The transformation (henshin) sequence is sacred in Sailor Moon. It follows a precise formula:

1. Trigger phrase: "[Planet/Body] [Power Word], Make Up!" —Inner Senshi use simple power words: "Moon Prism Power," "Mars Star Power" —Outer Senshi use grander phrasing: "Pluto Planet Power" —Your OC's trigger should match their celestial body's gravitas

2. Visual sequence: The transformation strips the civilian identity and rebuilds the Senshi layer by layer. Key elements: —A burst of the Senshi's signature color —Body ribbons or energy wrapping around the form —Each costume piece materializes individually (gloves, boots, tiara, bow) —A finishing pose with the celestial body or its symbol visible behind them

3. Duration: Transformations in Sailor Moon are unhurried and ceremonial. They're a ritual, not a quick change. Design the emotional arc of the sequence — vulnerability (civilian form stripped away), empowerment (Senshi form building), and declaration (finishing pose).

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Attack Naming Convention

Sailor Moon attack names follow strict linguistic patterns. Study these before naming your OC's techniques:

Inner Senshi pattern: [Elemental Noun] + [Action Verb/Mythological Reference]

• Fire Soul, Sparkling Wide Pressure, Shine Aqua Illusion, Supreme Thunder

Outer Senshi pattern: [Cosmic/Grandiose Noun] + [Dramatic Descriptor]

• Dead Scream, World Shaking, Deep Submerge, Silence Glaive Surprise

Power-up pattern: Attacks gain additional adjectives and become more complex names in later seasons.

• Burning Mandala, Star Serious Laser, Starlight Honeymoon Therapy Kiss

For your OC: Match the naming convention to their power tier. A newly awakened Senshi has simple two-word attacks. A mature Senshi has elaborate, poetic names. The progression should feel like the character growing into their power.

Example attack progression for Sailor Io:

• Base: Sulfur Flash
• Powered up: Volcanic Io Eruption
• Final form: Tidal Magma Cataclysm of Io

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Fuku (Costume) Design System

The Sailor fuku follows a template, but the details communicate everything about the character.

Fixed elements (all Senshi have these):

• Sailor collar with stripes
• Front bow with brooch
• Back bow (larger, trailing)
• Pleated skirt
• Tiara with gemstone
• Choker
• Gloves (elbow-length for most)
• Boots or heels

Variable elements (this is where your OC becomes unique):

• Skirt color = primary celestial association (Mars is red, Mercury is blue — your OC's should map to their body's palette)
• Bow color = secondary/complementary color
• Tiara gem = celestial body's signature color; shape can vary (round, oval, star-shaped)
• Collar stripe count = power level indicator in some fan conventions (1-3 stripes)
• Boot height = short boots for inner-tier Senshi, tall boots for outer-tier or more powerful characters
• Glove trim = accent color, sometimes matches bow
• Unique accessory = every Senshi has one. Mercury's visor. Mars's ofuda. Pluto's Garnet Rod. Your OC needs a signature item tied to their celestial body.

Color assignment process:

1. Research your celestial body's actual visual appearance (NASA images work well)
2. Extract 2-3 dominant colors
3. Assign: darkest = skirt, brightest = bow, mid-tone = trim/accents
4. The tiara gem should be the most saturated version of the primary color

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Senshi Role in the Hierarchy

Where does your OC fit among the Senshi?

• Inner Court (Mercury, Venus, Mars, Jupiter) — Guardian soldiers who protect the Princess directly. Combat-focused, social, team-oriented.
• Outer Court (Uranus, Neptune, Pluto, Saturn) — Sentinel soldiers who protect the solar system's perimeter. Isolated, powerful, willing to make sacrifices the Inner Senshi won't.
• Satellite Senshi (OC territory) — Senshi tied to moons or dwarf planets. Could serve as intermediaries, specialists, or independent operators who don't fit either court cleanly.
• Extrasolar Senshi (Starlights territory) — From other star systems. Outsiders with their own mission, their own Princess, their own war.

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Civilian Identity

Every Senshi has a civilian life that thematically mirrors their powers. Ami (Mercury) is a genius student. Rei (Mars) is a shrine maiden. Makoto (Jupiter) is physically strong and domestic.

Your OC's civilian identity should rhyme with their Senshi identity without being obvious. A Sailor Io OC might be a chemistry student (sulfur/volcanic chemistry), someone with anger management issues they're working through (volcanic temperament), or an artist who works with molten glass (literal lava adjacent).

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Prompt Strategy

Sailor Moon has one of the most recognizable anime art styles. Lean into it:

"A Sailor Senshi with long silver-blue hair in twin braids, wearing a navy and ice-white fuku with cracked-ice patterns on the skirt hem, a diamond-shaped tiara gem, elbow-length white gloves with blue trim, knee-high white boots, holding a crystalline staff, standing in a moonlit ice cavern — Sailor Moon 90s anime art style, sparkle effects, celestial background"

Essential terms: "Sailor Moon art style," "fuku," "tiara," "sparkle effects," "transformation pose" or "attack pose." Without the style specification, AI output drifts toward generic magical girl designs that miss the specific Sailor Moon visual language.

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Frequently Asked Questions

Can my Senshi be male? In canon, the Sailor Starlights transform from male civilian forms to female Senshi forms (anime version). The manga keeps them female in both forms. Male Senshi in the traditional sense don't exist in canon, but the Tuxedo Mask archetype (supportive warrior without a sailor fuku) is an alternative. Fan OCs have explored male Senshi extensively — the choice is yours.

Does my Senshi need to be from the Silver Millennium? Not necessarily. The Starlights have no Silver Millennium connection. An OC Senshi could be a newly awakened guardian from a celestial body that never had a Senshi before — or one whose ancient Senshi line was lost and is now restarting.

How powerful should my Senshi be relative to the canon cast? Dwarf planet and moon-based Senshi should generally sit below the Outer Senshi in raw power but can exceed Inner Senshi in specialized areas. A Senshi bound to Titan (Saturn's moon) being stronger than Sailor Saturn would undermine the canon hierarchy.

Can my Senshi have a unique fuku design that breaks the template? Minor variations (asymmetric elements, unique accessories, slightly different silhouette) are common in fan designs. Completely abandoning the fuku template makes the character stop reading as a Sailor Senshi. The template IS the identity.