Marginal Prince

A small island in the Pacific Ocean is home to a boarding school for high-class boys. The 16-year-old Yuuta gets the chance to study among the rich and famous of the world, and via his cell phone's video function, he is able to communicate with his older sister back in Japan on a daily basis, same as his friends he makes at the school. While Yuuta is trying to adapt to the new school and make friends, and his sister gets in contact with the other boys via phone more and more, something bad is going on behind the scenes...

Marginal Prince is based on a Japanese cell phone game for the NTT DoCoMo network, which was created mainly for girls and women. The game's goal is to have one of the boys fall in love with the player (although 'neutral' endings are possible as well) in a classic Dating Sim style, flavoured with speech recognition software. As the result of a finished scenario, a character will sing one song, of which most are also incorporated in the anime, and for which the series of 13 episodes might be most famous (possibly also thanks to the mostly well-known cast). A manga, drama CD and novel were released as well.

Tropes used in Marginal Prince include:

Adjusting Your Glasses: Sokurov and Haruya do this regularly.
All There in the Manual: Non-Japanese watchers will probably only understand little what is going on between and with the characters, as most of the backstories are only given on the game's website and only hinted upon in the anime.
The Anime of the Game
The Artifact: The ruby in the picture of St. Alphonso come off as this at first but it's not at all.
Beach Episode
Badass Labcoat: The school's doctor, Stanislav Sokurov, wears one. Complete with scalpels.
Badass Long Hair: Sylvain, Ivy, Sokurov
Bishonen: Quite naturally, since the game is aimed at young women and takes place in an all-boys school.
- Cast Full of Pretty Boys
Bishie Sparkle
Break the Cutie: Joshua at the peak of episode 13.
Chekhov's Gun: Yuuta gives a little bunny charm to Henri, who passes it on to Joshua later. He puts it to Yuuta's cellphone, which saves him from being stabbed in the heart.
Crash Into Hello: This seems to be Mikhail's hobby, and also happened between Yuuta and Alfred in the first episode.
Crossdresser
Crouching Moron, Hidden Badass: Sylvain, Ivy, Sokurov to some degree
- Funnily, all three also count as Badass Longhair.
Cute Shotaro Boy: Mikhail, sometimes also Yuuta.
Deadpan Snarker: Henri loves to snark at others, especially Alfred. Or sometimes at Yuuta. But mostly Alfred.
- His snarking is actually such a present part of his character that his absence in episode 6 is lampshaded by Alfred noticing that there's no one to comment on his performance.
Death by Childbirth: According to the games's website, Henri's mother died from giving birth to him.
Demoted to Extra: The pianist Shun Someya is a regular character of the game, but only appears in one episode of the anime.
Disappeared Mum: For some reason, less (if nothing) is known about most of the characters' mothers, but much more about their fathers.
Dude Looks Like a Lady: Henri and Mikhail alot, Sylvain to some degree.
Fan Boy: Sylvain takes this to the extreme with anything Japanese, while Yuuta fanboys after Alfred and the movies he starred in, as well as after Joshua at times.
Everythings Better With Bunnies: It's a punky robot bunny with a screw on its head, to be precise.
Fictional Country: The dukedom of Loreto, complete with Succession Crisis. There is an Italian city by the same name, though...
Four Eyes, Zero Soul: Due to something that happened between the two some years ago, Henri has begun to talk of Sokurov as sadistic, as heared on the drama CD.
Gratuitous Foreign Language: The episode titles are built on the system of "[Japanese Word] [Japanese Genetive Particle] [Foreign Word]". They use English, Spanish, German, French and Latin. Also, Henri throws in some Gratuitous French from time to time.
Ho Yay: as almost expected from a series with an all-male cast, although the game itself is aimed at a male-female relationship. The anime has subtext of Joshua/Henri, Joshua/Yuuta and Yuuta/Mikhail for Fan Service.
I Have Your Wife: the main reason for Sylvain to perform the army tasks he does is because his parents are being kept away from him, and he only gets to know their location after fulfilling his mission.
I Just Want to Be Loved: the game website states that the incident around Henri's birth made his father grow rather cold to the boy. As a result, Henri is said to crave for love.
Image Song: Every episode had at least one of the boys singing, in episode nine, there were even three songs. Most of them were produced for the game, but a few exclusively for the anime.
Improbable Weapon User: Sylvain can fight off bad guys with a yoyo... He also tends to fanboy over it sometimes.
Large Ham: Sokurov and also Alfred. The latter is voiced by Masakazu Morita, btw.
Missing Episode: At least for western audiences - a fourteenth episode was added to the last DVD as an extra.
Modest Royalty: Joshua, heir to the throne of Loreto, does not really seem to care for his status and generally keeps it unmentioned and does not want to become king anyway. He dresses casually like the others (when not wearing the school uniform) and generally behaves like a quite normal teenager.
Named After Somebody Famous: Henri-Hugues de Saint Germain and Alfred Visconti
New Transfer Student: The central plot of the anime evolves around Yuuta trying to get adjusted to his new environment and get around with the people in his dorm.
No Export for You: The only thing international fans have, and will probably ever have, are fansubs of the anime.
Parental Abandonment: Most characters' parents (or one part of them) are either dead or seemingly otherwise not interested in their children, at least not enough to have the boys talk about them.
Older Than They Look: honestly, would you think Mikhail is 16...?
Raised by Grandparents: Haruya, as it seems. Joshua was raised by his uncle after first his father, and then also his mother had died.
Red Oni, Blue Oni: Alfred and Henri
School Uniforms Are the New Black
Scary Shiny Glasses: Sokurov, (almost) all the time.
Screw the Rules, I Have Connections: Yuuta comes from a very normal Japanese family, with no great talent, name, fame or money that would be needed to enter the school. He is only there because a rich man noticed his interest for art.
- Also, Joshua, the Student Council President, saves him from being expelled from the school due to confusion with his documents.
Skilled but Naive: Sylvain, but it might be just a facade.
Spell My Name with an "S": before Yenje had any official material with his name written on, many referred to him as "Enju", based on how his name sounds and is written in katakana.
The Stoic: Henri most of the times, Yenje almost even more.
Strong Family Resemblance: Joshua, on the one hand, looks very much like a direct mixture between his mother and father, and on the other hand very much like his ancestor, Saint Alphonso, the school founder. Also Henri, who looks almost exaclty like his mother.
Surrounded by Idiots: Haruya suffers from this in episode 5. His adventure companions Alfred and Yuuta are really "bothersome" to him.
Sweet Tooth: Yenje
Three Amigos: Alfred, Sylvain and Haruya, forming the rock band "Dead Prince".
Those Two Guys: Sokurov and Ivy
Too Dumb to Live: Mikhail in epoisode nine.
Truth in Television: Alfred is mentioned to be the grandson of Luchino Visconti, a famous movie director. Henri belongs to the family de Saint Germain; the game website them being into winery and hotel business. Google makes it quickly clear that both is true, as well as the existence of certain rumors about the Count de Saint Germain that are mentioned in episode 6.
You Gotta Have Blue Hair: Henri's hair is blue, Joshua's is green, Haruya has purple hair (or rather, lavender), Sylvain's is pink... the list goes on.