Hayato Mikogami, also known as the Ashikabi of the South, is a character from the second season of the Sekirei anime, Sekirei: Pure Engagement. He is fifteen years old and comes from an exceptionally wealthy family, serving as an academic prodigy who graduated from a university in the United States at a very young age. Despite his intellectual achievements, his home life is marked by loneliness, as his affluent parents are neglectful and largely control his life from a distance, leading him to attend a prestigious school primarily for the sake of his family's social status.

Mikogami has a complex and multifaceted personality that shifts throughout the narrative. Initially, he displays a cruel and spoiled demeanor, viewing the Sekirei Plan as an exciting game and the Sekirei themselves as collectible items to be acquired. He is determined and demanding, showing little tolerance for failure from his own Sekirei and pursuing his goals with a disregard for morality, such as when he attacks a researcher to capture a young, unwinged Sekirei. He can also appear carefree and cheerful, particularly in his interactions with his first and most trusted Sekirei, Mutsu. Despite his often immature and selfish actions, he holds a strong respect for the official rules of the Sekirei Plan and despises those who break them, which sets him apart from other more unscrupulous Ashikabi. Underneath his villainous exterior lies a lonely teenager whose wish for excitement and companionship is fulfilled upon becoming involved in the Sekirei Plan. While he sometimes dismisses his Sekirei as useless after defeats, flashbacks and later events reveal he feels genuine sorrow at their loss and values his collection's safety, developing a deep care for them as they alleviate his isolation.

Mikogami serves as a secondary antagonist and rival in Sekirei: Pure Engagement. He controls the southern section of the city where the competition takes place and is driven by the motivation to capture and wing as many Sekirei as possible. His ultimate goal is to gather all the Jinki, powerful items central to the competition, and become the champion of the Sekirei Plan, which he views as the ultimate exciting game. His role in the story often places him in opposition to the protagonist, Minato, whom he dislikes for thwarting his plans, though he will intervene on Minato's behalf against rule-breakers out of a sense of fairness.

His most significant relationship is with his first Sekirei, Mutsu, who recognizes and defends Mikogami, becoming his devoted partner despite an initial preference for a female Ashikabi. His other notable Sekirei include Akitsu, who was originally discarded by another Ashikabi, as well as Himeko, Mitsuki, and Taki. Throughout the Sekirei Plan, Mikogami undergoes notable development. His initial view of Sekirei as disposable tools evolves into a genuine appreciation and love for them as individuals who brought joy and purpose to his lonely life. This growth is most evident during the Fourth Stage of the Plan, where after losing several of his Sekirei in battle, he expresses his deep desire not to lose anyone else. This sincerity allows Akitsu to finally be fully winged, and he is later overwhelmed with emotion when his fallen Sekirei are revived.

As an Ashikabi, Mikogami's notable abilities are not physical but strategic and intellectual. He is exceptionally intelligent and cunning, capable of predicting his opponents' moves and using his family's vast wealth and connections to gather information and stay ahead of the competition. His combat effectiveness relies entirely on directing his powerful Sekirei, such as Mutsu, who possesses immense strength, and Akitsu, who wields ice-based abilities.