Seika Ayanokoji (綾小路 聖香 Ayanokōji Seika) is one of Host Club's former, regular customers and the antagonist of the first episode of the anime. She is seen only twice in the anime as she appears in Ep 01 - Starting Today, You Are a Host! and Ep 13 - Haruhi in Wonderland!. She also appears in Chapter 01 of the manga. Her first name is only revealed in the dorama.
Ayanokoji has long reddish-brown hair that has bangs hanging on the left side and blue-grey eyes. She is usually seen wearing the Ouran Academy Girls' uniform, even when appearing in cameos in either the anime or the manga.
Ayanokoji is of royal descent, hence her legitimate title of "Princess." She is adept at putting on a pleasant facade when, in reality, she is a highly possessive and mean-spirited young woman judging from what she does to Haruhi Fujioka during their first interactions in Starting Today, You Are a Host!.
Ayanokoji is one of Tamaki Suoh’s regular customers who becomes jealous of the attention he gives to Host-in-Training Haruhi. Her jealousy prompts her to toss Haruhi's belongings out of a window and into a garden fountain below, then request Haruhi's company in order to "set her straight" about Tamaki's interest. Haruhi realizes that Ayanokoji is jealous and when she states this fact, the selfish girl knocks over the table at which they're sitting, causing Haruhi to land on top of her. Ayanokoji then accuses Haruhi of being a pervert and assaulting her. However, Hikaru Hitachiin and Kaoru Hitachiin realize the truth and dump pitchers of water on top of her. A wet and drenched Ayanokoji sputters and cries for Tamaki's help. In defense of his rookie host, Tamaki banishes Ayanokoji from the Host Club saying she's unwelcome because, "Haruhi is not that sort of man." Ayanokoji is hurt by his words and says "But why, Tamaki?" before she flees from the club crying "You idiot!".
Ayanokoji is one of Tamaki's regular customers and is seen frequently with him in Starting Today, You are a Host! and Chapter 1. Ayanokoji seems to be a possessive sort of person who becomes jealous easily or is just a very controlling person who needs to be "the smartest, prettiest, richest girl in the room," especially where Tamaki is concerned. It may be speculated that she harbors genuine feelings towards him, though he only treats her as a guest; making his somewhat sincere interest in Haruhi a threat to her position in his heart.
Ayanokoji is instantly envious of the attention given Haruhi from Tamaki and immediately begins to shower cruelty on the rookie host. She almost succeeds in framing her for assault, but the Host Club manages to see the truth and Ayanokoji is banned from attending Host Club ever again. It is unknown if she ever becomes aware of Haruhi's gender.
- (To Haruhi) But you went too far bothering Tamaki-sama. It was only for that cheap bag, right? Don't think that he loves you. Tamaki-sama is taking good care of you because your family background is new to him. Maybe all those weird things are happening because you are tagging along Tamaki-sama without thinking...?
- (To Tamaki) Help!! Haruhi-kun suddely became violent!!
- (To no one in particular) Waaaah~ Stupid Tamaki-sama!!
- The name Seika means "sacred" (聖 sei) and "fragrance" (香 ka).
- Seika's surname Ayanokoji means "design" (綾 aya), "small" (小 ko) and "pathway" (路 ji).
- It is unknown if Seika recognizes Haruhi as a girl when she first meets her, which would explain her jealousy with regard to Tamaki.
- Seika is in the same class as Mitsukuni "Honey" Haninozuka and Takashi "Mori" Morinozuka.