Akane the Kunoichi

The brave heroine of the game. She is a kunoichi for Goro.

Cleavage Window: Her outfit exposes a bit of her chest.
Ms. Fanservice: Her outfit sure exposes a lot of skin.
Purple Is Powerful: Her outfit being purple notes her awesomeness and power as an kunoichi.
Scarf of Asskicking: Akane sports a rather nifty scarf. She still wears it when she wears her "charming kimono" in the Golden Ending.

Goro

An noble samurai. He is Akane’s master.

All Your Base Are Belong to Us: Becomes a victim of this when Hiromi’s forces attack and occupy his castle.
Badass in Distress: A noble samurai gets kidnapped. Should qualify for something.
Chick Magnet: The intro shows a crowd of kimono-clad women who love him, and his ninja Akane, who really loves him.
Hidden Depths: He likes charming kimonos, according to his Steam Card. Which is a obvious hint explaining your need to gather the Lost Charming Kimonos to him.
Samurai Ponytail: He sports one to reflect he is a noble samurai. It notably looks closer to the classic chonmage style.

The main bad guy (er, gal) of the game.

All Your Base Are Belong to Us: Is implied to have attacked Goro’s Castle before or after capturing Goro himself.
Cleavage Window: She appears to have more of her chest exposed compared to Akane.
Flunky Boss: In the final fight, she summons mooks to fight against you, which gets refilled.
Generic Doomsday Villain: Why exactly is Hiromi kidnapping Goro? We're never told. All that is to know is that she is evil and must be stop.
Non-Action Big Bad: In the final boss fight, she doesn't fight you directly, but instead commands her ninjas and dogs to attack.
Obliquely Obfuscated Occupation: It is not exactly clear what job Hiromi holds in comparison to Goro (a samurai) and Akane (kunoichi). All that seems to be clear is that she owns ninjas and her own manor, implying some high form of power.
- Subverted now, as Haruneko officially states that she's a "vicious ninja master" on a Steam discussion. [1]
Purple Is Powerful: She supports a different hue of purple from Akane, but nonetheless fits to show her status.