Chapter 82

The Ultimate Ally (最高の協カ者,) is the 82nd chapter of the Bungo Stray Dogs manga.

Summary
In the special United Nations headquarters in Standard Island, VIPs from various nations convene to vote on the founding of the intended Supranational Armed Defense Force, envisioned as a stateless anti-terrorism corps. Some perceive such idea to be quite ambitious and nothing more than a pipe dream, while others wish to have it established for the sake of underground and illegal methods against other nations given its statelessness. Before casting their votes, Fukuchi, the soon-to-be commander of the forces, arrives to issue a statement to the councilmen, making them starstruck with the legendary war hero.

Fukuchi begins his speech with a light-hearted tone, later transitioning into a serious mood, addressing how they are already losing in the current war against terrorism. Because of the development of advanced sciences and certain abilities being weaponized for crime — the Decay of Angels being on its vanguard — Fukuchi claims that the world can no longer be protected with the typical framework. Hence, he stresses on the importance of fighting back, especially on a global span of banding together in combating evil. To concretize this vision, he hopes to have the intended stateless troops, which he names the Humankind Army, to be established through their votes. As he leaves the final decision to the councilmen, they laud Fukuchi for his enthralling speech.

As he enters his quarters, Ranpo greets him and commends his excellent speech. Ranpo gives him a chance to report his presence to security, but Fukuchi calls the security asking not to let anyone enter his room for five minutes. Ranpo and Fukuchi exchange pleasantries upon reuniting again since the founding of the Armed Detective Agency, which was also when Fukuzawa told Ranpo of his deep trust in his childhood friend Fukuchi, whom he fondly called as Gen'ichirō. Ranpo then states his reason for visiting Fukuchi, which was to join forces with him as ordered by the President to defeat the Decay of Angels.

Fukuchi initially refuses his offer, disappointed that the great detective has come to bargain with him with no persuasive technique or tactic whatsoever, and shuns their poor planning. Ranpo claims that he can instantly deduce his responses and even psychologically induce Fukuchi to cooperate with them, but he chooses not to. Instead, Ranpo merely places his trust in Fukuchi simply because Fukuzawa asked him to believe in Fukuchi — after all, his ultimate rationale is to face the same direction as the President. Moved with how Fukuzawa has such great comrades, Fukuchi agrees to the deal, and they both head out to escape safely.

Aboard the Boswellian, the disguised Atsushi spots Ranpo and Fukuchi arrive after the successful negotiation. As they infiltrate the ship, Atsushi marvels at Fukuchi and steels himself not to make an error in dealing with him, since the survival of the Agency depends on Fukuchi's alignment. Fukuchi warns Atsushi and Ranpo of guards aboard the ship from several national affiliations who would shoot them if given the chance. Ranpo casually teases Fukuchi, compelling Atsushi to advise the detective to mind his language towards Fukuchi. The latter does not mind, thinking that Ranpo's attitude towards him is merely fueled by jealousy due to Fukuchi's longer time spent with Fukuzawa in their youth compared to Ranpo.

Later, Atsushi wonders who Kamui really is, but Ranpo urges him not to make haste as per the President's orders. Ranpo gets flattered that Atsushi only wants to see his Super Deduction in action, though he refuses his subtle request. Nonetheless, after Atsushi offers him a Ramune, Ranpo agrees to use his "ability" to deduce the identity of their ultimate enemy mastermind once and for all.