*1. Untold Origins Situation: Fukuzawa meets Ranpo, and their first case eventually leads to the creation of the Armed Detective Agency. Kaia is not yet involved with the Agency. As an orphaned child suffering from recurring illness, she is taken in by Mori, who begins treating her and monitoring her unusual condition. He becomes one of the few adults she trusts. Kaia: Childhood/background only.

2. 2.

   Fifteen Situation: Fifteen-year-old Dazai investigates the former Port Mafia boss and encounters Chūya. Mori's leadership and the Mafia's internal conflicts dominate the story. Kaia is older than Dazai and Chūya and is already under Mori's protection. Her illness remains unpredictable, but her Dragon-Lightning ability makes her exceptionally dangerous. Kaia: Port Mafia background.

3. 3.

   Storm Bringer Side Situation: The aftermath of Dazai and Chūya's Fifteen-era history expands into another major Port Mafia conflict. Kaia remains one of Mori's strongest executives during this period. Her illness forces occasional medical evaluations, creating short private scenes between her and Mori at Mafia headquarters. Kaia: Active Mafia supporting role.

4. 4.

   Storm Bringer Situation: Chūya's connection to Arahabaki becomes central as the Port Mafia confronts powerful enemies and questions surrounding his existence. Kaia serves as one of Mori's dangerous assets and assists when necessary. After missions, Mori personally checks her condition because excessive ability use can trigger severe flare-ups. Kaia: Active Mafia supporting role.

5. 5.

   Dark Era Situation: The Port Mafia's darker world is explored through Dazai, Oda, and Mori. Kaia is already a highly dangerous Mafia Executive, feared for her Dragon-Lightning ability. She occasionally shares quiet moments with Mori at the Mafia headquarters, where he checks her health. She begins questioning whether she belongs in the Mafia. Kaia: Official active role.

6. 6.

   Azure Apostle Situation: Kunikida and Dazai investigate a dangerous case involving the Azure King. In the original novel timeline, this occurs before Dazai joins the Agency; the anime rearranges the story. Kaia is already considering leaving the Mafia and eventually chooses a different path, preparing to become part of the Agency. Kaia: Transition/background role.

7. 7.

   Port Mafia Situation: Atsushi becomes involved with the Agency while Akutagawa and the Port Mafia pursue him. The conflict between the two organizations escalates. Kaia has already abandoned the Mafia and is now an adult member of the Agency. Her former position as Executive makes her knowledge of Mafia operations extremely valuable. Kaia: Official active role.

8. 8.

   Guild Situation: The Guild arrives in Yokohama and launches a massive attack against the Agency. Kaia fights alongside the Agency while her former Mafia knowledge helps her predict criminal tactics. Her Dragon-Lightning ability becomes particularly useful against large-scale threats, although prolonged combat risks triggering her illness. Kaia: Official active role.*