Seika Kohinata (小日向星華, Kohinata Seika) is a third year Obelisk Blue student who appears in the Yu-Gi-Oh! GX manga and Miss Duel Academy for the past two years. Her name is similar to the word "snake."
Seika is one of the five final contestants shortlisted for the title of Miss Duel Academy. During the final round of the contest, it is revealed that Alexis Rhodes has the same number of votes, and that one of the Duel Academy students hasn't cast his or her vote. When that student is identified as Jaden Yuki, one of Alexis' friends, Seika suspects the whole thing is a ploy orchestrated by Alexis to claim the title, when, in fact, neither Jaden nor Alexis have any interest in the contest, as proven by Alexis' reluctance to participate and Jaden's dislike of voting. Seika then challenges Jaden to a Duel for his vote, but Alexis decides she'll Duel him instead. If Jaden wins, his vote will go to Seika, while if Alexis wins, she's allowed to drop out of the competition, making it a win-win situation for Seika. During the Duel, Seika is surprised by Alexis' intensity and passion, since all she had to do was "settle the pageant." Seika begins to understand that Alexis wants to be taken as a Duelist rather than simply a female, and realizes that she is Dueling with her heart and soul. Even though Jaden wins in the end, Seika decides that Alexis should be Miss Duel Academy as she has proven to be better qualified.
Seika is later shown talking to Zane Truesdale before the Tournament finals. Zane comments that it is unusual for Seika to show any interest in actual Dueling, and that it's a "first" for her. Seika later reveals that she is in the tournament to defeat Jaden after his involvement in her dethroning as Miss Duel Academy, and to prove herself.
Seika is very touchy, and easily upset or infuriated as proven during her Duel with Jaden in the Tournament finals. She also seems to nurture grudges, which is indicated from her planned revenge on Jaden, making her temperament similar to the monsters she uses.