OVA
Description
Natsume Honma is Aya Iseshima's classmate and closest friend at the story's beginning. She presents herself as a supportive, non-combatant figure, seemingly unaware of the Martial Hearts tournament and frequently expressing concern for Aya's well-being during her fights. This persona is entirely false.

Natsume is the daughter of Kumi Honma and sister of Haruki Honma. Her mother, Kumi, and aunt, Yumi Kazuki, were subjected to sexual slavery after losing a previous Martial Hearts tournament to Aya's mother, Suzuko Iseshima. Kumi suffered permanent mutilation, including the removal of her vocal cords, rendering her mute. This event forms the basis of a vendetta. Natsume, alongside her brother Haruki and their cousin Miko Kazuki (Yumi's daughter), was raised and groomed by Kumi to exact revenge against Suzuko and her family. Their plan involved manipulating Aya into participating in a reconstructed Martial Hearts tournament.

Miko initially joined the tournament feigning a desire for friendship before withdrawing and disappearing, creating a pretext for Aya to take her place. Natsume maintained her facade as Aya's concerned best friend throughout the tournament, offering encouragement while secretly orchestrating events with Haruki and Miko. Their ultimate goal was to subject Aya to defeat in the tournament, leading to mental enslavement and sexual slavery, mirroring Kumi and Yumi's fate.

The conspiracy extended beyond Aya. Natsume, Miko, and Haruki were directly responsible for the treatment of other tournament losers. After each defeat, competitors like Azusa Suma, Rei Kakizaki, and the Daimonji sisters were mentally broken through torture and transformed into mindless sex slaves under their control. Natsume participated in this systematic cruelty.

In the final confrontation, Natsume, Haruki, and Miko revealed their true motives and roles as masterminds to Aya, taunting her with the depth of their deception and the suffering inflicted. They aimed to deliver Aya to Kumi for final punishment. Suzuko intervened, killing Natsume, Haruki, and Miko to save Aya before perishing herself. Natsume's fate is sealed within this cycle of violence and retribution.