Fafnir

Fafnir (ファフニール Fafunīru) or Takeshi Ooyama (大山 猛 Ōyama Takeshi) is a supporting character in the series. He is Makoto Takiya’s roommate and friend.

Appearance
In his human form, Fafnir appears as a handsome young man with long, straight black hair in a loose ponytail with bangs covering his right eye with small glasses on the bridge of his nose & red eyes which can change color and size depending on when enraged. He has a calm, collected demeanor that reflects his slightly gloomy face. He is mostly seen in his butler attire and a mail coach cravat tie.

When Fafnir is in his dragon form, he appears as a towering dark dragon with 3-4 pairs of pure red eyes.

He is also able to transform into a monstrous humanoid form with purple skin, a bulky upper body, a mouth with several rows of big and sharp fangs as teeth and two horns.

Personality
At the beginning of the series, Fafnir abhorred humans for everything they were. As the series goes by, his heart warms up to a human with similar interests and takes on a sensei-student style friendship with Makoto Takiya. His hatred for humans turns into more of an indifference to them, and more of a pain to get to know them rather than just kill or ignore them. He appears to dislike spicy food, as when Takiya made some curry, he asked if it was "mild" and refused to eat Tohru's soup after learning that it was spicy.

He became extremely attracted to video games and other Otaku interests since his lifestyle of a cursed dragon can easily accommodate it. He is hardworking and diligent for his passions as seen with his multiple all-nighters to play games (dragons don't need to sleep to stay healthy and active). Fafnir is shown to be fairly greedy as in a videogame, he went for the treasure chest (which was a mimic) ignoring Takiya's warnings not to do so.

Background
Most of Fafnir's past is shrouded in mystery. What's known is he lived his life in a cave protecting his treasure and gained displeasure towards humans as they constantly invaded his home to steal it. He joins the Chaos Faction as he felt his actions and interests (like doing curses) aligned with them. He becomes acquainted with Tohru as fellow dragons from the Chaos Faction. The two first met when she wanted to rest in his cave, but Fafnir declares that the space they share would be decided on their combat abilities. She one time asked his opinion regarding the system surrounding humanity and dragons. He answers how it's pointless to think of such things and one should just do as they please or they can't call themselves a true dragon, even if they have to kill their own family.

Plot
Fafnir debuts in episode 1/chapter 1 as a voice on the receiving end of a phone call Tohru makes when she tries to ask what is meant by "holding the fort", which Kobayashi tasked Tohru with doing while she goes to work. Fafnir is the first dragon other than Tohru to be mentioned in the anime or manga.

Fafnir debuts in person in episode 3/chapter 8, being invited to the party Kobayashi is holding at her new apartment. He takes an interest in the video game Takiya is playing.

Fafnir plays a dodgeball game against those that bullied Riko Saikawa, then against the other dragons, in episode 4/chapter 21.

In episode 5/chapter 15, Fafnir announces his intention to live in the same world as Tohru. After Kobayashi refuses to house Fafnir, he goes to sleep in a mountain, returning the next day to news of a "mysterious creature spotted". Tohru has to convince Fafnir to live with humans by helping him find a place to live. On their way to the estate agent, Fafnir questions Tohru's relationship with humans. The estate agent kicks out Fafnir and Tohru after the former offers a gold nugget. Eventually, Tohru remembers that Fafnir got on well with someone at the party, and goes to visit Takiya with Fafnir. Fafnir decides to stay after trying out several other video games that Takiya has.

In episode 6, Fafnir helps Takiya with a video game the latter is developing. The following day, they go to a game shop together. When both are ready to go home, Fafnir acknowledges that Takiya is a "hit".

In episode 7/chapter 17, Fafnir participates at Comiket selling a book of curses. Tohru has a look at the book and sees that Fafnir had printed "real, effective curses". As a result, Fafnir's book fails to sell.

In episode 8/chapter 23, Fafnir appears as one of the judges in Tohru and Kobayashi's "bento lunch competition" for Kanna. During the competition, he questions Kobayashi's relationship with dragons, in contrast to Lucoa's acknowledgement of them.

In episode 10, Fafnir initially dismisses the invitation to be part of Tohru's show at the retirement home, but later offers to direct The Little Match Girl by first holding auditions for the title role. Tohru, Elma and Riko all fail auditions under Fafnir, who then relinquishes the director role. In the first rehearsal of the play directed by Elma, Fafnir fails in his role as the title character's father, so he and the other dragons decide to improvise the play. Fafnir is eventually cast as a stranger with the power to designate people as magical girls. His role in the play ends after Lucoa, taking on the role of a magic fairy, prevents Fafnir from forcing the magical girls to fight each other for one staff.

In episode 11, Takiya mentions that Fafnir failed to sell a single copy of his second book of curses during Winter Comiket. Fafnir buys an "evil-banishing arrow" at the First Shrine festival on New Year's Eve. He later watches the first sunrise of the new year with Takiya.

In episode 12, when Takiya returns home in rain, Fafnir asks him to join in "guerrilla warfare".

In the OVA, when Takiya returns home, Fafnir sends Takiya a "Valentine's Blade" when playing their online game. He later joins Takiya, Kobayashi, and the other dragons on a visit to a spa resort.

Powers
Fafnir can create very potent curses. The incantations for the curses he writes are so powerful that even a human without magic can curse someone with it.

Like the other dragons he can transform into other forms but he's shown to have three instead of the typical two which are: dragon form, bipedal-demon form, and a human form.

It seems Fafnir can use portals just as easily as Tohru and Lucoa. As when he decided to live in the human world Tohru didn't express her worries on him not being able to return home.

Like all dragons, Fafnir's physical strength far exceeds that of a normal human. However, it would also appear his strength exceeds Tohru's as he was able to effortlessly catch a ball she threw, then send her flying back upon throwing the ball back to her.

In terms of other powers is unknown, but is has been said by Tohru that she has yet to win a one-on-one duel from him. Which could entail that he is stronger than her.

Makoto Takiya
Takiya is Fafnir's human roommate/friend and the person who introduced Fafnir to video games. Both Kobayashi and Tohru were surprised when he accepted Fafnir as a roommate without question or worries. The two eventually bonded close enough to the point where Fafnir who has been infamous of being solitary in his past accepted a nickname that Takiya made just for him, stating that he "doesn't mind it". Fafnir eventually got comfortable enough with the Otaku lifestyle that he tags along with him to conventions and helps him set up, later on setting up his stand (without being to sell even a single copy of his works, though).

Tohru
Tohru seems to be his friend and possibly a student. She often calls him early in the story to ask for his advice. The two seem to share mutual respect and care for one another's well-being to an extent; helping out each other at a moment's notice to their best knowledge.

Kobayashi
Not much interaction is shown between the two but despite Fafnir's hostile first impression on her, Kobayashi seemingly went along with it and the two seem to respect one another's boundaries. He doesn't seem offended by Kobayashi's outright rejection of Tohru suggesting him to stay in the Kobayashi residence but neither does he seem to hold the place in any specific significance compared to the rest of the dragon cast. Nevertheless, both Kobayashi and Fafnir doesn't seem to mind one another's person's company.

Quetzalcoatl
Little is known of the two's relationship if at all, but the two don't seem to mind each other's company. Both of them, however, share a similar trait in that Tohru regards them both as her seniors or teachers, often asking for their advice. Comically albeit logically, Tohru's 1st choice for advice is always that of Fafnir but brushes it aside for Lucoa's more sane and practical suggestions instead, as his advice is always "kill them", be it about guard duty or laundry.

Elma
Both Fafnir and Elma enjoy a level of grandeur evident in their joint play for the elderly.

Kanna
Unlike Tohru, Fafnir doesn't show any particular bond with Kanna nor does he hate her companionship. The two often interact on a similar way to that between Tohru and himself but at a distance in comparison.

Trivia

 * Fafnir bears a resemblance to Sebastian Michaelis from Kuroshitsuji as they both have the same appearance and the same Japanese voice actor.
 * Fafnir also has a strong resemblance to Alucard from the Castlevania franchise in his 21-century alter-ego, Genya Arikado.
 * Tohru calls him "Mr. Fafnir".
 * Fafnir is also the name of a dragon in Norse mythology, who is the son of the dwarf King Hreidmar.
 * It is hinted that Fafnir used to be fully human and later gain the ability to transform into a dragon.
 * Fafnir created a circle for Comiket and sold a volume with actually effective and often lethal curses - he was unable to sell a single copy.
 * Fafnir true resp. dragon form is 20 Meters Tall.
 * Fafnir's dragon form bears a striking resemblance to the Ogdru-Jahad from the Hellboy comics.
 * He's the only supporting character to not feature horns or a tail in his human form.
 * He is the only dragon so far to have another form rather than Human or Dragon.