Arguably the main character, and a staple of Otomedius' promotional art. Anoa is a bright and cheerful girl with a penchant for blue. Her Ride Viper is the Vic Viper. When not saving the world, Anoa is a second year high school student at St. Gradius Academy.
Awesome but Impractical: Hyper Anoa. The concept of her becoming more powerful as her Platonic power grows is great from a story perspective, but when it happens in gameplay, it strips all of your powers and weapons, leaving you to face the final stage with default speed, no weapons, and no options.
Also, Anoa's Platonic Break. By the time it's charged and ready to fire, the enemies it's locked on to are most likely off the screen. It's impressive though when used on bosses.
A Gradian. Erul is Anoa's best friend, and came to Earth as part of a search for her older brother, the pilot of VIXEN (a ship from one of Konami's earlier shooters). She's quite intelligent, and enjoys studying Earth culture. Her Ride Viper is Lord British. Erul is a second-year student, in the same class as her friend Anoa.
Frickin' Laser Beams: Lord British's signature weapon, Ripple Laser, fires expanding laser rings that still destroy enemies that fly through the center.
Shout-Out: Her brother was the pilot of VIXEN, from Gradius II: Gofer no Yabou. Another is her credit dialogue in Gorgeous, quoted word-for-word from the Salamander OVA.
Esmeralda: "What are you going to do now?" Erul: "Well...I'll think about it while listening to some rock music."
Stuff Blowing Up: Erul's Platonic Break, where she positions her Options and then detonates them.
A third year student and the closest to being an adult in the cast, Diol is the squadron leader. She's firm, but has a sisterly kindness to her approach on leadership. She seems to be bonded to the Flint, an organic component of her otherwise artificial Serenity Viper.
Shout-Out: Her tentacle tail resembles those found on the Flint in the original game.
Workaholic: A rare, upbeat version. Diol loves her work for the "G" Organization and can't seem to put it down.
In her ending cutscene from Gorgeous, Diol announces that the mission is complete and she wants another one, because her "work is never really finished." Anoa and Erul promptly complain about the work load, but she just laughs it off.
An immigrant from Planet Mel, Madoka is an engineering genius who built her own Ride Viper - Which is based on Twinbee, a hero from her planet. On Earth, she's a first-year high school student.
Art Evolution: Madoka underwent significant design changes between Gorgeous and Excellent.
Of note, she wears shorts now, instead of a skirt. She's also opted for Twinbee's iconic gloves.
Murdoch Viper now has handles for her to hang on to. Additionally, the seat now physically resembles Twinbee's body, with the cushion itself replacing the windshield/eye portion. It's also referred to as Murdoch Viper Mk.II.
Dumb Blonde: Completely inverted, as she's a mechanical genius. She's still just a first-year student, though.
Enemy Summoner: The rare heroic version, Madoka's Platonic Break summons a duplicate of Gainbee who punches the crap out of enemies for a while.
In Excellent, she summons a Shooting Star enemy who swoops through, unleashing a variety of attacks along the way.
Wrench Wench: Built her own Ride Viper completely from scratch, before she even saw any of the others.
Hailing from another dimension, and the planet Ebisuboshi, Emon Five is the only male in the entire cast. While he himself is inspired by Ganbare Goemon, his Xel Viper is drawn from Thunder Cross. Emon is (was?) a second year student in Anoa's class.
Rated M for Manly: The character designer, Mine Yoshizaki, explains in an interview that Emon's unusual position on Xel Viper was chosen so that the hitbox being below his waist would make it look like he tanked enemy fire with his chest.
Shout-Out: The character for Five is 'Go'. Read in Japanese, Emon's full name is Go Emon.
A Bacterian, Tita is a spacey girl whose body is rife with cybernetics. She flies the Big Core Examiner, and has a terse relationship with the rest of the squadron, being the same race as their primary enemy. Tita aspires to win their trust, though doesn't understand humans very well. Tita is in Madoka's class, as a first-year student at St. Gradius.
The Time Travel in Excellent suggests that her defection was fairly recent, as her access codes were still usable in Dark Force's fortress.
Tita: "I wonder if my clearance codes still work... ...Hm...This should be adequate."
Human Aliens: Bacterian. This is an important story point for Tita, as everything she does is to try and get the other Angels to accept her as one of their own despite being the same species as their worst enemy.
Kill Sat: Tita's Platonic Break invokes this by calling down a spread of high-powered lasers from the sky.
Another pilot from Planet Gradius, Esmeralda is a formal and businesslike tactician and weapons expert. She's a reference to the popular Gradius Gaiden, and pilots Jade Knight. Despite her cold and curt exterior, she seems to have a weakness for cute things. Esmeralda is in Diol's class, as a third year student.
Curtains Match the Window: Despite the rampant color-coordination of the entire cast, she's the only one who actually displays this. And even then, it's tentative, being a noticably different shade of green.
This is carried over in Excellent, in that Esmeralda can use everything except for the character specific weapons, of which there are 1 per character (or 2 in the cases of Strarf, Kokoro, Gesshi, and Poini).
Esmeralda's wingman, Poini is a surprisingly young girl with an equally surprising intelligence. Like Esmeralda, she's a reference to Gradius Gaiden, piloting Jade Knight's partner ship, Falchion Beta. Also like Esmeralda, Poini is in Diol's class at St. Gradius, as a third year student in spite of her age.
Precocious Crush: Appears to have one on Esmeralda. She gets jealous of Diol's being cast opposite her in the school play during the credits to Excellent, the two are constantly paired together by the games, and then there's the cleavage dive.
Vocal Dissonance: When she shifts into English dialogue, Poini's voice actress tends to slip into a deeper, more womanly voice than Poini's usual childish pitch when speaking Japanese. This is most evident during her Platonic Break and Burst attacks, where it sounds like a completely different person calling out "Crush all of them!"
A samurai girl who references Getsu Fuma Den. Fuuma and Kokoro come to Angel Squadron to replace Emon. She's a very no-nonsense sort of girl who takes her job and her training very seriously. She lives by the code of bushido, though seems to be unaware of the history of her family name as she does not recognize Ryukotsuki.
Fan Nickname: Fuuma Nameicantpronounce was circulating amongst English-speaking fans who had trouble remembering her complex surname (back when the translation was thought to be Fuuma Getsushihana).
A translation error has also led to Fuuma being referred to as "Mon Hau".
Konami has finally settled on her name being Gesshi Hanafuuma, which is a little easier to handle. The nickname seems to be falling into disuse.
Summon Magic: With Poini's new Black Hole Platonic Break, Gesshi gets her old homing dragon, though it's somewhat nerfed because Gesshi has no Options to speak of.
A girl who references Konami's popular Castlevania series. Kokoro is an all-business sort of girl who works hard so that she can live up to her noble lineage. She compliments Gesshi's samurai sensibility quite well. Kokoro's Ride Viper is Stavros.
An Axe to Grind: Has access to an exclusive Double-type weapon called "Axe" which pierces enemies in the parabola it travels and causes a lot of damage; however, this comes at the expense of the weapon being tough to aim and use effectively.
I Just Want to Be Normal: Secretly. Kokoro differs from other characters of this type in that she already knows and accepts that she can't be normal, and while she has fun in her civilian life and likes hanging around with the other Angels, on missions she's completely focused on eliminating the enemy, not even allowing herself to get upset when her allies are hurt or killed. She needs to live up to her family name, after all.
Also gets access to the exclusive weapon Beam Whip.
A robot girl from the Busou Shinki series of collectable figurines. She's a very demure and even shy person who tends to keep to herself. She dislikes combat and lacks the motivation for it, so tends to default to her programming. She contrasts with her playful and active sister in more ways than one. Arnval's Riding Viper is Anthurium.
Arnval's partner, also from Busou Shinki. Strarf seems to be optimized for night combat, and otherwise is a very active girl compared to her subdued partner. Strarf's main system imitates psychic powers, which she exercises with many of the weapons systems on Alpinia. Unlike Arnval, Strarf is a very active and playful girl who is very curious about the world of humans.
Mind over Matter: Strarf's exclusive weapons PsyCom and Mindblast utilize artificially-generated psychic powers to manipulate weapons on Alpinia. The first is a homing laser while the second is a short-range force wave. Additionally, she uses this to control her Platonic Break attack.
Red Oni, Blue Oni: The Angel/Devil pair seems to have this going on with their personalities, with Strarf being Red.
Norse Mythology: Hugin and Munin are the servants of Odin. They live in Valhalla.
Only Known by Initials: It's never explicitly stated what R.B. and L.B. stand for. It's generally believed to be Right Brain and Left Brain, given the physical shape of their predecessor, a giant brain named Gofer.
Verbal Tic: Ends most of her sentences with "nya".
Neko Sencho: "I'm no 'fraidy cat! I'm an air-sea-landcat, the purrfect feline warrior-nya! I'll bat you around like a ball of string-nya!"
Warm Up Boss: Generally considered easy, even in high loop play.
Bait-and-Switch Boss: The stage initially seems like you'll be fighting the Gofer Sisters in a Tetran, which you can damage throughout the level. And then they take off down a side-street and T.B. leaps out with a perfect-condition Tripod Core.
A three-armed demon lord from a distant hell who was slain a long, long time ago. The Gofer Sisters resurrected her so they could use her power against the G Organization's newest members, Kokoro and Gesshi.
Expy: She's basically a Goth-Loli version of Castlevania's Dracula — an anthropomorphic force of evil who seemingly wants to destroy everything. Highlighting this, the first phase of her boss fight takes place in a castle/cathedral for no immediately obvious reason. Tita even comments that these Bacterians are different, and Kokoro says her family has a history of dealing with this sort of thing.
Tyke Bomb: Either she's the current leader of the Bacterians, or the Gofer Sisters created her as a Person of Mass Destruction. No matter which one it is, even when she's in her larval stage, she's very powerful.
Heel-Face Turn: For unexplained reasons, assists the Gradian fleet against the Bacterians during a mass assault. In the final stage, he's coordinating the fleet's repairs and pursuit of the routed Bacterian ships.
The Unfought: In Gorgeous, he's hanging around and you hear his laugh at one point, but you never fight him. He appears again in Excellent and again is not a boss. Considering that he's undergone a Heel-Face Turn in the finished product, fighting him might be difficult.
What Could Have Been: Was originally going to be the last bonus boss of Excellent, but this was given to Dark Force's final form, and his role in the plot was reworked.