this was a pain in the butt to edit, but I really like this pic
Sailor Neptune - Kaioh Michiru

Real Name: Kaioh Michiru Name meaning: mature sea king Birthday: March 6 Zodiac Sign: Pisces Height: 5'5"
Senshi Position: Outer Senshi
Element: ocean
Fighting Style: offensive
Secret Weapons: Deep Aqua MirrorFavorite Color: marine blue Hobbies: collecting cosmetics Favorite Subject: music Worst Subject: none Favorite Food: sashimi Favorite gemstone: aquamarine Family: ? (they were never really mentioned Dream: to be a violinist Seiyuu: Katsuki Masako

Michiru is a person of many, many talents. She's naturally smart, doesn't even have to study for school. She can paint very well, at least in the anime, and it shows one of her paintings, called "Space", hanging in a museum. She is also a musical prodigy, she plays the violin. Her violin playing has made her famous; in one episode she bounced a lemon up and down on her violin while playing it (although that's actually physically impossible...sorry, but I play the violin and believe me, it's not).
She's mostly serious, and in SMS she's extremely dedicated to finding the Talismans. But she also likes to joke around sometimes, especially when she's around Haruka or the other senshi. Michiru can be a bit jealous sometimes. Especially of other girls who flirt with Haruka (and this happens a lot). But then, Haruka's the same way. She has an elegant, refined way of speaking and presenting herself in general, and there's probably never a time when you'll see Michiru looking at all ungainly, clumsy, or anything unlike her graceful, articulate self (nope, not even in super-deformed pictures ^_^) 
She sometimes appears to be self-involved or stuck up, but she's not really. She's just kind of arrogant. Not arrogant like Yaten, like oh-I'm-so-great-everyone-worship-me arrogant. More like Haruka: they both know they're smarter, richer, and more powerful in general than most other people, but they don't go around screaming it out to the world. Of course, she's practically perfect and she has a right to be stuck up, but usually she's not. Most people, I think, would be at least a little stuck up if they were demigoddesses like Michiru. 
Michiru as a senshi is very dedicated, both to her duties and her partner. Hers and Haruka's ultimate mission in S was to find the three Talismans that form the Holy Grail, and to keep Sailorsaturn, the Silent Messiah, from awakening. The reason they worked in a pair was so that if one died or was unable to continue the mission, the other would take over. Of course, neither of them wanted that to happen, but they had to be prepared just in case. In the Silver Millenium, their job as Outer Senshi was not to guard Princess Serenity as the Inners did. They had to guard the Moon Kingdom itself, being more powerful and the first ones to get hit if there were an invasion. 
Now, onto Michiru's relationship with Haruka. Yes, people, they are lesbians (Jerry Falwell, go away). Just accept that, okay? Anyway, both Haruka and Michiru are very dedicated to one another, and are a great example of how, no matter what gender (or race, or religion, or whatever), if two people love each other that's all that matters. Oh, by the way, that BS that SOS spread about how Haruka was really Prince Uranus and stuff is just that, BS. Naoko even said herself that they were supposed to be lesbians. If you think about it, it kinda makes sense that Haruka and Michiru, two near-perfect human beings, would pair up, since there's no one else that could compete with them. Michiru probably wouldn't get too many prospective dates out there in the real world, because she'd most likely intimidate every man she met (heck yeah, if I were a man I'd be intimidated). And same with Haruka. I mean, it's not every day that a guy would go out with a girl who's taller and possibly more masculine than he is, not to mention one who is also nearly perfect. So it's logical that two perfect girls would pair up with one another, having no one else as good as each other, and I'm not making any sense am I? Oh well, the point that I'm trying to get across is that I think they're perfect for each other. 

Neptune Planet Power, Make-Up
What Michiru says to transform into Sailor Neptune.

Deep Submerge
Neptune says this and is surrounded by water while she creates a ringed ball of blue energy.  She throws it at her enemy and it has the force of an extremely strong tidal wave.

Submarine Reflection
Sailor Neptune uses her Deep Aqua Mirror for this attack.  She holds it out and it reflects beams of blue light at her enemy and blasts them away.

Deep Aqua Mirror
One of the Talismans, the one that Neptune possesses.  It is used to see the truth in all things.

Transformation Pen
What Michiru uses to transform into Sailor Neptune