Naoki Miki is a character created for the anime adaptation of Sword Gai: The Animation. He serves as a Chrysalis, a human who wields a cursed weapon, and operates as an agent for the shadowy organization known as the Shoshidai, which is dedicated to collecting and containing such dangerous armaments. Miki is an anime original character, meaning he does not appear in the original manga.

Miki has a history with the Shoshidai, but the specific details of his past and how he came to possess a cursed weapon, the Fallgon Sword, are not clearly defined in the story. He is a capable combatant, possessing enhanced physical abilities and resilience that come with being a Chrysalis. At one point, his transformation progresses to the point where he temporarily becomes an Armed Demon, a more powerful and monstrous state, showcasing his willingness to undergo great personal risk for his missions.

In terms of personality, Miki is portrayed as a competent and dedicated agent. He forms a strong bond with Marcus Lithos, another Shoshidai operative, whom he considers a friend. He also shares a secret romantic relationship with Mina Hiraya, a fellow member of the organization, which provides an emotional anchor for his character. His motivations are tied to his duty to the Shoshidai and his desire to protect those he cares about, including his girlfriend and his comrades.

Miki plays a supporting role in the larger conflict surrounding the various cursed weapons. He is sent on missions to retrieve artifacts, such as the Azoth Sword, and later participates in a covert operation alongside Marcus to acquire a legendary halberd. Physically, he has short brown hair and brown eyes, and his attire varies from a Shoshidai uniform and suits to a leather jacket and tactical gear when on assignment.