Tatsuhiko Shido

Adaptational Badass: TV series Shido is significantly more powerful than game Shido. Game Shido is actually a dhampyr, and his powers are limited to low-level super strength/agility and the ability to extend his fingernails into blades. (The blood manipulation power seems to have been planned for the abandoned sequel game, some of the design docs for which were incorporated into the anime.)
Badass Longcoat: A regular feature of Shido's second design.
Bloody Murder: Shido can use his blood as a weapon. In particular, he can change it into a sword.
Brainwashed: In the past by Cain.
Even the Guys Want Him: While he shows a preference for women, (and they are often receptive,) Cain certainly wants him.
Friendly Neighborhood Vampire: A vampire detective who only feeds on the willing.
Frozen Fashion Sense: Wears Edwardian era clothing - though he usually leaves the top hat in his office.
May–December Romance: By the end of the series he requites Riho's feelings for him and they become a couple.
No Name Given: Shido's name is just an alias. While this is great for the mystique factor, there's also the justification that he suffers from Identity Amnesia.

Yayoi Matsunaga

Voiced by: Emi Shinohara (JP), Mari Devon ^note (EN)

Action Girl: She is a secret agent, and engages in gun battles and car chases at various points.
Angsty Surviving Twin: Subverted. Her twin sister's soul resides in her, and she seems content with this as she did everything to save her (which also makes her immune to be turned into a vampire).
Badass in a Nice Suit: She favors business-like clothes, but with very short skirts.
Cool Car: A red Aston Martin DB7.
Fair Cop: While Yayoi is not a police officer in the show, she is one in the game, and she is young and attractive in both continuities.
Facial Horror: As a child, she accidentally burned her face by trying to lit up her birthday cake's candles. Her sister Kasumi later left her face for her before dying.
The Team Normal: Unlike the other members of the main cast, she does not have (or gain) supernatural powers.
Voluntary Vampire Victim: She is a willing donor to Shido, providing him with Nightbreed related cases to solve in exchange for her blood. It helps she is immune to vampire bites thanks to an incident involving a Nightbreed.

Clingy Jealous Girl: Rather mild case. She wants Shido's affection, and initially is jealous of Yayoi since Shido spends so much time with her. Riho is less clingy after she becomes a Secret-Keeper.
Friendly Neighborhood Vampire: Undergoes an Emergency Transformation in episode 4. She becomes a sort of apprentice to Shido, who continues to protect her while showing her how to get by as a vampire.
Girl Friday: Shido hired her out of pity for her situation (see below: Parental Abandonment) to do office chores that probably don't even need doing.
May–December Romance: After she becomes a vampire she actually has a shot with Shido, despite an age gap of centuries. Their romantic relationship begins with string-pulling by Cain, of all people.
Parental Abandonment: Riho's parents were killed by a Nightbreed.
Plucky Office Girl: She wants to do more than fetch Shido's coffee, and her persistence in trying to prove herself to Shido gets her on the wrong side of the Masquerade.

Voiced by: Ikue Otani (JP), Sandy Fox (EN)

Adaptation Dye-Job: Guni's design only has minor differences in the two parts of the TV series, but has very different coloration when compared to the game. Guni's original coloration has brown skin, white hair, and solid red eyes.
Barbie Doll Anatomy: Always appears nude, but has no visible naughty bits.
Fairy Companion: She self-proclaims to be this to Shido.
Head Pet: In the original game, Guni inhabits Shido's ear and can be seen popping in and out of his head. The early part of the reflects this by showing Guni emerging from Shido's hair, but the later parts of the show drop this.
Snarky Non-Human Sidekick: She is sassy and suitably impish, but really has a Hidden Heart of Gold.

Agent Peacock: He has all of Shido's powers, but as The Older Immortal they are more potent and he uses them more ruthlessly. And he looks just a good as Shido does while using them.
Big Bad: Shido’s main enemy and the one who turned him into a vampire in the first place.
Canon Foreigner: Cain did not appear in the original game, which completely bypasses vampiric offspring drama.
Charm Person: While certainly capable in combat, his main methods of interfering with Shido are glamours and illusions.
Depraved Bisexual: He does not show much interest in anyone but Shido, but there is that one flashback scene...
I Love You, Vampire Son: His main motivation (besides enacting the Golden Dawn, wherever that was supposed to lead) is getting Shido, whom he views as a son/lover, back under his thumb.
Long-Haired Pretty Boy: In the second designs, his appearance is more youthful and he has long blond hair.

Stalker with a Crush: He is a Psycho Ex, and he can (and does) show up anywhere.
Whip of Dominance: Just as Shido can use his blood as a sword, so Cain can use his as a whip, which is apropos given he's a domineering and possessive Agent Peacock who wants to take Shido back by force.