!The Galilei Sisters
* AffectionateNickname: They refer each other with nicknames.
* BlondeBrunetteRedhead: Hazuki, Kazuki and Hozuki, respectively.
* ButNotTooForeign: Half-Japanese on their father's side.
* ColorCodedCharacters: Hozuki is red, Kazuki is blue, and Hazuki is yellow
* FreudianTrio: Hazuki is TheMccoy, Hozuki is TheKirk and Kazuki is TheSpock.
* HeroicLineage: Direct descendents of Galileo Galilei.
* MultiEthnicName: Japanese given names, Italian surnames.
* RedEyesTakeWarning: The three of them have reddish-purple/magenta eyes.

!Hozuki Ferrari
!!Voiced by: Creator/RinaHidaka
The youngest sister at age thirteen, as well as the most brilliant. Shy and apologetic, but also extremely dangerous thanks her versatile arsenal of inventions.
* AffectionateNickname: She is called Hocchii or Hocchibi by her sisters.
* AnimalMotif: Goldfish.
* ApologeticAttacker: She's ''really'' sorry she destroyed your HumongousMecha, Mr. Bad Guy.
* BadassAdorable: Cute, tiny, awkward... has a self-built arsenal of high-tech weapons, including a flying mecha-goldfish with homing missile launchers and a machine gun. She is afraid to use them, but that won't stop her.
* BeautyIsNeverTarnished: [[spoiler:Falls from several stories high ''onto a pile of cars'' in episode four,]] and doesn't have so much as a scratch or bruise.
* BewareTheNiceOnes: They ''may'' employ heavy artillery.
* ChildProdigy
* DaddysGirl: And is not happy that the new security arrangement means she'll have to live with mom instead.
* GadgeteerGenius: builder of a transforming rocket-scooter-gun and a flying mecha-goldfish, among other things.
* GirlishPigtails
** FlowerInHerHair
* ILetGwenStacyDie: [[spoiler:She still feels rather unnerved by Leo's death and her inability to stop it; when Roberto starts a killing spree at the hospital, she's the one to stop him, remembering her lost friend.]]
* [[spoiler:KidFromTheFuture: When she ends up in Galileo's time.]]
* KidHero: Well, she's 13. But her childish personality certainly counts.
* PottyEmergency: Has a brief case of this in Episode 5.
* ScienceHero
* TeenGenius: Only thirteen years old and she's already creating impossibly high-tech gadgets.
* TokenMiniMoe: The youngest character of the series.
* WrenchWench

!Kazuki Ferrari
!!Voiced by: Creator/RumiOokubo
The middle sister, a seventeen-year-old high-schooler. Moody and lovelorn, but also a capable blackbelt.
* ActionGirl: [[BadassInANiceSuit Black-suited]] man on top of you with a knife to your throat? Just crush ''his'' throat in first.
* AffectionateNickname: She is called Kakki by Hazuki.
* AllLoveIsUnrequited: She has a crush on an as-of-yet unnamed boy at her school, but her fugitive status will likely keep her from getting the chance to confess.
* AloofDarkHairedGirl: Most of the time.
* HomeSweetHome: Kazuki really wishes her sisters would drop her off at home and leave her out of the whole "globetrotting fugitives" thing.
* IJustWantToBeSpecial: She's very jealous of Hozuki for her technical skills, and wishes that she could also live up to her lineage in terms of sheer talent.
* IneffectualLoner: Known for skipping classes to escape group activities.
* MiddleChildSyndrome: Good God, yes.
* MsFanservice
* ProperTightsWithASkirt
* RefusalOfTheCall: She's very eager to give the Adni Moon company what they want, thinking that they'd let them go and leave them alone, allowing them to return to their normal lives.
* SecondYearProtagonist
* SmittenTeenageGirl: Introduced skipping class and mooning over an unrequited crush.
* ThirdPersonPerson

!Hazuki Ferrari
!!Voiced by: Creator/KeiShindou
The oldest of the three sisters, twenty years old and studying law. Unfortunately for her, her late-night partying is threatening to get her flunked out of school.
* TheAlcoholic: Sometimes doesn't even wait for the sun to go down before getting smashed.
* BigSisterInstinct
* BraidsOfAction
* {{Cloudcuckoolander}}: Her reaction to being slammed against the wall by a kidnapper? Attempt to negotiate an out-of-court settlement.
-->'''Hazuki:''' Sexual assault is a felony! You'll get ten years for rape! Add assault to that and you can get a death sentence! We can settle out of court, but if you don't let me go ''right now'', I'll press charges!
* CoolBigSis
* CrusadingLawyer: Well, at least she ''wants'' to be.
* ForGreatJustice!
* GivingSomeoneThePointerFinger: When listing off a criminal's transgressions.
* HardDrinkingPartyGirl
* HotBlooded: Gets really fired up about law, even if she's not terribly good at it.
* LethalChef: According to Kazuki.
* NiceGirl: She insists on giving some of their scarce food supplies to a homeless man they meet, she says that that's the right thing to do and people should help each other out.

!!Voiced by: Creator/HiroshiKamiya
An Italian SkyPirate chasing after something referred to as "Galileo's Inheritence" who's oddly affable even when he's threatening to blow someone's head off. Enjoys flirting with the enemy, if only to annoy them. It turns out that most members of his band of Sky Pirates are people who were running away from abusive households and bad circumstances. He wants Galileo's Inheritance so that he can ensure they life comfortably and freely.
* AFatherToHisMen
* AffablyEvil: He'll even invite his hostages to watch the World Cup prelims with him.
* BadassBandolier
* BadassLongcoat
* BigDamnHeroes: He pretty much saves the girls in episode 3.
* BraidsBeadsAndBuckskins: Despite not being remotely Native American.
* CardCarryingVillain: Regardless of whether or not he's ''actually'' evil, he certainly loves playing the part - just look at the grin on his face when he declares "WeWillMeetAgain!"
* EvilRedhead
* FoeRomanticSubtext: From his interactions with the Galilei Sisters, it's hard to tell if he sees them as {{Worthy Opponent}}s or just has a giant VillainousCrush on Hazuki.
* TheGadfly: Especially when it comes to Hazuki.
-->'''Cicinho''': Girlie, what's your name?
-->'''Hazuki''': Hazuki Ferrari. Got a problem with it?
-->'''Cicinho''': Love it! Let me call you Bambina.
* GogglesDoNothing: Except inform you that he's a SkyPirate
* GratuitousItalian: How else would you know he was from there?
* HonorBeforeReason: Calls off his own attack on "Bambina" and her cohorts because they were distracted by [[spoiler:Hozuki's almost-mortal injury]], so he felt it wasn't a fair fight.
* JerkWithAHeartOfGold
* LaughablyEvil: Cicinho appears to have gone into piracy not for the treasure but for teh lulz.
* LoveAtFirstPunch: While Hazuki didn't ''exactly'' punch him, when she [[HotBlooded stood up]] and [[GivingSomeoneThePointerFinger verbally punched him]] it made him get interested in her.
* LovableRogue
* TheOnlyOneAllowedToDefeatYou: Sorry, Roberto, but the privilege of screwing with Bambina (and thus Hozuki and Kazuki by proxy) is Cicinho's alone.
* SailorPonytail
* SkyPirate
* TermsOfEndangerment: Dubs Hazuki "Bambina" and flirts with her just to annoy her.
** AffectionateNickname: Doesn't take long for "Bambina" to turn into this.

!Anna Hendrix
!!Voiced by: Creator/MarinaInoue
A self-admitted Galileo afficianado who wishes to track down or puzzle out anything he's ever left behind. She originally found herself in a situation not too different from the girls' upon learning of the Galileo Tesoro while researching her idol. She resolves to help the girls find Galileo's Inheritance and save their parents.
* [[spoiler:AllLoveIsUnrequited: With Roberto.]]
* AnimeHair: Capable of hiding a cell phone.
* [[AscendedFanboy Ascended Fangirl]]: ''Very'' happy to go on a globetrotting adventure with the descendants of Galileo.
* BigDamnHeroes: She's the one to save Hazuki at the start of the series, and is in no small part responsible for the girls' escape.
* [[spoiler:DoubleAgent: Is apparently working for Roberto.]]
* GreenEyes
* [[spoiler:LoveMartyr: She is willing to die for Roberto if necessary, but according to her, he couldn't care less.]]
* [[spoiler:ObliviousGuiltSlinging]]
* {{Otaku}}: She's a Galileo otaku

!Roberto Materazzi
!!Voiced by: Creator/TaitenKusunoki
-->"Death knows neither time nor place. It is fair and merciless to all, Cassini."

Heir to the Adonimoon Company and dead-set on locating Galileo's Inheritance at any cost, up to and including murder. He hates people who are uncivilized and weak. He thinks that the world is overpopulated and that the uncivilized are mere leeches upon society.
* [[spoiler: AnArmAndALeg: His left arm and right leg are prosthetic. He lost them in the disaster that killed his parents, but got new limbs after the president of Adni Moon adopted him.]]
** [[spoiler: ArtificialLimbs]]
* CharacterTic: Making origami.
* CorruptCorporateExecutive
* DarkAndTroubledPast: Originally, he came from a wealthy family who taught him the importance of selflessness. Then a disaster that he barely survived killed his parents.
* {{Expy}}: Of [[Franchise/AceAttorney Phoenix Wright]].
* FreudianExcuse: His hatred of those he feels are drains upon society (read: pretty much anyone who isn't prim and exceptional) comes from how [[spoiler: the homeless people his family fed chose not to help him when his parents were killed in a disaster, and instead chose to steal from his mother's corpse and ignore him when he was nearly crushed by debris.]]
* [[spoiler:HappilyAdopted: Sort of.]]
* AManOfWealthAndTaste
* RedAndBlackAndEvilAllOver
* [[spoiler: StartOfDarkness: The deaths of his parents, along with the callous disregard the homeless people they had previously feed gave to the situation.]]
* SocialDarwinist
* TheStoic: Calm, collected, and almost unflappable.
* TallDarkAndHandsome
* [[spoiler: UsedToBeASweetKid]]
* TheUnfettered
* WouldHurtAChild: Sometimes, the situation calls for the murder of a child or two.
* WickedCultured

![[spoiler:Galileo Galilei]]
!![[spoiler:Voiced by: Creator/YuukiKaji]]
[[spoiler:Yes, the real one. Hozuki travels to the past, falling on his aircraft. He's currently studying a strange phenomena on the sky. He has no idea Hozuki's his descendant.]]
* [[spoiler:BeethovenWasAnAlienSpy]]
* [[spoiler:BirdsOfAFeather: With Hozuki, of course.]]
* [[spoiler:Bishounen]]
* [[spoiler:CampStraight]]
* [[spoiler:HairOfGold]]
* [[spoiler:IntelligenceEqualsIsolation: TruthInTelevision. The real Galileo Galilei was tried and put into house arrest for his groundbreaking theories. He tells Hozuki about how alienated he got by everyone, to the point he didn't even want to discuss his dreams with anyone until she arrived.]]
* [[spoiler:LongHairedPrettyBoy]]
* [[spoiler:TeenGenius: Well, ''duh.'']]
* [[spoiler:TimeTravelRomance: He falls in love with Hozuki. He's blissfully unaware that she's actually his descendant, mind you.]]
* WalkingSpoiler