Essential Builds – Sailor Mercury

Manipulating water is her power,

Misting foes, and rain showers.

With a micro-miniature super computer,

She is the one named Sailor Mercury. 

Welcome to Essential Builds, the blog that turns popular culture icons into Essence20 Player Characters through a sparkling transformation sequence. 

I’m Ryan Costello, one of the designers of the Essence20 system and an author on the G.I. JOE, Transformers, and My Little Pony Roleplaying Game Core Rulebooks. As of this writing, I’ve written over 300 000 words for Essence20, contributing to over a dozen products and counting. 

I should say up front, I’m not the biggest fan of Sailor Moon. That’s because when it came out I was young and stupid. Which isn’t to say I didn’t watch it. In fact, I watched as much as I could. In the mid-90s, I’d get home from school before my brothers, just in time to watch the first 20 minutes of an episode of Sailor Moon. Then, when my two younger brothers got home, I changed the channel, right around the transformation sequences. I did not want anyone to know that I was totally into this show. 

Around the introduction of Rini, that station stopped airing new episodes. And, again, feeling self-conscious about my love for the series, I made no effort to track the rest of it down. Which is especially a shame because one of the big draws for me was the serialized storytelling. I was left with dangling threads! 

As is standard for an ensemble cast, fans become especially loyal to their favourite character. My favourite Sailor Scout (and yes, I’ll be using the Western dub interpretation and vocabulary) was Sailor Mercury. 

Building Essence20 Sailor Mercury

When I plotted out the first volley of characters I wanted to build for this blog, I noticed Power Rangers Roles didn’t get a lot of love. Their Role Perks apply to a lot of characters, but the Setting Perks—It’s Morphin Time and Zords—don’t have a lot of flexibility. 

I needed a show with Super Sentai tropes that wasn’t associated with Power Rangers or any of the shows it imported. Sailor Moon fit that description. Though very different tonally, both Power Rangers and Sailor Moon feature teenagers (with attitude, by certain definitions of the word) gaining super powers from an otherworldly force to fight monsters. Now, the Power Rangers fight their biggest foes with mecha, something not present in Sailor Moon. After conferring with noted Sailor Moon fan Cathy, I thought I had a fun solution for that. We’ll get there. 

But first…

Who Is Sailor Mercury?

She’s the Sailor Scout with a visor. 

If you want me to like your character, giving them a visor gets me 90% on board by default. But she packs a lot into that last 10%.

By day(light), Sailor Mercury is Amy, Crossroads Middle School honor student. Not just book smart, she’s the brains of the team, leading computer research sessions between adventures and using her micro-miniature super computer to analyze threats and look up information on the fly. 

Her connection to Mercury gives her water and ice powers. She uses gusts of conjured water to push foes around, chilling winds to capture them, and mist and bubbles to obscure her movements. 

Physically, Sailor Mercury is the smallest Sailor Scout. She has blue hair, with the Sailor Suit to match. How appropriate…


Blue Spectrum (Power Rangers Core Rulebook)

In both Power Rangers and Sailor Moon, the blue one is the smart one. Maybe I’m just used to Ninja Turtles and G.I. Joe, where purple is the smartest colour, but I see this as a happy coincidence. Evidently, I’m not the first person to make this connection

At 1st level, she gains two Perks from her Role: “It’s Morphin Time”, which turns Amy into Sailor Mercury; and Eureka!, which gives her a pool of Idea Points that she can spend to gain an Edge on Smarts-based Skill Tests. Great start fulfilling her concept as the brains of the team. 

At 2nd level, Helping Hands lets her heal allies as a Free action. Not specifically a power we’ve seen Sailor Mercury use, but healers tend to be absent from most media even though they’re dominant in roleplaying games. Between her helpful nature and the health benefits of water, giving Sailor Mercury a healing power makes sense in game terms. 

Also at 2nd level is her first of many Grid Tech Perks. This is the most Sailor Mercury Perk her Role gives, with a lot of options that give us flexibility in how we interpret her. Aptitude Augmenter lets her reroll 1s and 2s when using a chosen Skill. Applying this to either Science or Technology cements her as the Sailor Scout who can find the answers when faced with something weird. Of the three other Grid Tech options available at this level, Gridspeak Receivers, which lets her and her team understand and read any language used by creatures on the Morphin Grid, matches what we’ve seen her do the most. I avoid reskinning as much as possible on this blog, but given that the Grid is exclusively tied to Power Rangers, we’d need to change this to a Sailor Moon enemy power source, like the Dead Moon Kingdom.

Two of the three remaining non-Grid Tech, non-Zord, and non-Grid Power Perks from the Role expand on the idea that Sailor Mercury supports her teammates. Power Infusion lets allies reroll 1s, and Power Burst grants teammates extra Power Points. Both useful, both on-theme. 


That brings us to our Zord. Cathy had a few suggestions here. She said that the weapons from SuperS all had some level of sentience. I didn’t think that hit the mechanical mark of what the Zords Perks give to a character. Plus, Cathy second guessed whether that applied to all Sailor Scouts or just Sailor Moon. Next she brought up that the live action adaptation had magical tambourines that turned into weapons. Both of these suggestions fit the Power Weapon (which I’ll get back to) motif more than Zords. As it was, I was only half paying attention to her by that point, because her first suggestion was instantly my favourite. 

“The western toy line came out with some sort of moon cycle, but that was based on absolutely nothing in canon”

Indeed it did!

That was perfect.

Well, near perfect. It was clearly a Sailor Moon motorcycle, but it’s not hard to imagine that if the Moon gifted Serena with a Moon Cycle, Amy must have a Mercury Cycle to zip around with. And I know some Power Rangers teams have vehicle Zords instead of beast Zords. I just needed to use one of those. 

And that’s when I found out that the two cycles in the rules so far, the Strata Cycle and Vector Cycle from Power Rangers Roleplaying Game: A Jump Through Time, were non-Zord vehicles. 

Sadly, that means I have to leave this section of the character sheet blank. As the only Core Rulebook I had no part in writing, the Power Rangers rules are my biggest weakness as an Essence20 designer, and it would take me too much time to find a suitable alternative for this admittedly already weak connection to the source material. So, for the sake of this build, Sailor Mercury rides a giant robot triceratops into battle. 

Grid Powers

This was another area I thought would be easier than it turned out to be. Surely there were Grid Powers that let Rangers unleash a torrent of bubbles! Then I realized, those kinds of power were the domain of Power Ranger villains. The heroes used martial arts and weapons, not much in the way of elements.

That said, I did find one Grid Power that gave a Cold attack. Cryogenic Touch from Power Rangers Roleplaying Game: A Jump Through Time. Unfortunately, it only applies to melee attacks. For the rest of her water-based offense, I can give her Power Weapon the Power Weapon Element Damage Assignment Weapon Upgrade. Just ignore that Sailor Mercury charges into battle with a Blade Blaster. 

The other Grid Powers on my radar are Future Vision, another Power from Power Rangers Roleplaying Game: A Jump Through Time, and Mnemonic Recall from the Power Rangers Roleplaying Game Core Rulebook. One gives her insight into the future, the other the past. 


Brainy (Power Rangers Core Rulebook)

After struggling more than anticipated to make a Power Rangers Role fit the theme, you might wonder why I’m going back to the Power Rangers well here. It’s because Power Rangers has the perfect Sailor Mercury Origin. 

Power Ranger Origins work really well for characters with secret identities, because they highlight who the character is all day, everyday. They’re all about the personality that shines through even when they assume their alter ego. Amy is brainy. Everything about the Brainy Origin applies, especially the Origin Benefit, “I Remember Reading About…” which gives her temporary Specialization in a Smarts Skill. I wouldn’t be surprised if she actually starts a line like that in the Anime. 


1st: Bookworm (My Little Pony Roleplaying Game Core Rulebook)

Precise (My Little Pony Roleplaying Game Core Rulebook)

Student (Power Rangers Core Rulebook)

I thought about only choosing Power Rangers options for this build, but there are too many good Influences in My Little Pony to ignore. 

What’s funny is that I found myself drawn to the Influences for the Hang-Ups more than the Perks this time. For example, while Student’s Perk works for Sailor Mercury, that area of her character is already covered pretty well with the Brainy Origin and the Future Vision and Mnemonic Recall Grid Powers. What none of those options capture is Amy’s mousy nature and tendency to internalize her self-doubt. However, suffering a Snag when performing a task related to her area of study not related to the actual subject at hand does. Similarly, Precise has a Hang-Up that gives her a Snag when she suffers damage, which shows that Sailor Mercury is the least combat capable of the Sailor Scouts. And, bonus, Precise’s Detail Oriented Perk ties in nicely with her Cryogenic Touch Grid Power. 

Essence Scores and Skills


A lot of this build’s options apply to Smarts Skills, without any of them applying to a specific Smarts Skill. That means we can spend our Smarts Skill Points broadly. We’ll raise Science and Technology as high as we can afford, followed by Culture, and then a couple of Ranks in Alertness. When the group needs Amy to know stuff, she’ll be able to reliably beat most Culture, Science, and Technology Skill Test DIFs. We can go easy on Alertness since it’s the Smarts Skill the rest of the group probably has Ranks in, and we’ll skip Survival entirely. It’s just not a Skill Sailor Mercury used in source material. 

Next we look at Speed. Since Cryogenic Touch affects Finesse, we’ll make that Sailor Mercury’s melee Skill. And she needs Targeting to aim her bubble blasts. I think this is a build that can survive not having any Ranks in Initiative, although one could be useful. 

Here’s where the build gets odd. Sailor Mercury’s characterization as meek and mild makes both Strength and Social Skill investment a low priority. Do I go with the most generic options, Athleticism and Persuasion? Or maybe Deception because every time she says she’s fine, it’s a lie? She doesn’t get many Essence Score Increases in either, but the fewer Skills we spread those Ranks across, the more it seems like she’s focused in those areas. Like, how could I justify giving Sailor Mercury +d10 in Brawn? Or the highest Health in the group?

So, I imported the Spellcasting Skill from My Little Pony. Spells like Barreling Beam and Don’t Notice Me Field line up with ways she’s used her water powers, while Bestow Expertise and Take Record line up with what she can do with her micro-miniature super computer. She’ll need to wait until she gets a General Perk at 4th level to cast the spells, but that’s OK. She can use Spellcasting as a knowledge Skill while she waits for the Magical General Perk to unlock her spellcasting abilities. She has some water-based powers from her weapon and Role in the meantime. And hey, slowly unlocking more powers is definitely a Sailor Moon trope. 

General Perks and Other Options

Sailor Mercury gets so many other options that realize her powers and personality, General Perks just aren’t a big part of this build. I already mentioned needing Magical, and we’ll take that at 4th level. Compassionate from My Little Pony adds versatility to what she can do in social scenes, and the spellcaster General Perks continue to elevate her prowess with magic. Then there’s Team Player from G.I. Joe and Transformers, which generates Story Points for using Lend Assistance. The nice thing is, there’s enough flexibility in theme and mechanical direction that it’s easy to justify most General Perks. 


I thought building a Sailor Moon character on a Power Rangers chassis would be easy. I didn’t anticipate so many tropes of the one that do not fit the other. Luckily, I was able to create a fully functional and source accurate Sailor Mercury build, just with some extra features. Extra giant sentient war machine features. I guess instead of creating a Sailor Moon accurate Sailor Mercury, I created a Sailor Scoutin Power Rangers mashup. 


G.I. JOE Roleplaying Game Core Rulebook

My Little Pony Roleplaying Game Core Rulebook

Power Rangers Roleplaying Game Core Rulebook

Power Rangers Roleplaying Game: A Jump Through Time

Transformers Roleplaying Game Core Rulebook

Ryan Costello

What started as one gamer wanting to talk about his love of a game grew into a podcast network. Ryan founded what would become the Know Direction Podcast network with Jason "Jay" Dubsky, his friend and fellow 3.5 enthusiast. They and their game group moved on to Pathfinder, and the Know Direction podcast network was born. Now married and a father, Ryan continues to serve the network as the director of logistics and co-host of Upshift podcast, dedicated to the Essence20 RPG system he writes for and helped design. You can find out more about Ryan and the history of the network in this episode of Presenting: