- "Welcome! To the utopia, the 'Beach'! I understand well. You guys are seeking 'answer'."
—Boshiya in the manga Chapter 15.
Takeru Danma with the alias of The Hatter (帽子屋, lit. "hat merchant") is a character first appears in the Beach arc. He was the leader of the Beach society and represented the "idealistic sect" of the Beach residents, as opposed to Agni's "martial sect".
Danma and Agni had been sworn friends 10 years before they entered the Borderland when they were 16 years old. Danma affectionately addressed Agni "Mori-chan" for watching his back while fighting other street thugs. Later he worked as a gigolo in the Kabukichō red-light district. Just before entering the borderland with Agni, Danma succeeded his deceased father's hat shop, hence his later alias "Hatter".
After winning few games, Hatter realizes that the Borderland is unchangeable. Inspired by Gandhi's motto, "be the change you want to see in the world", Hatter convinces Agni, An, Kuzuryu, Mahiru and Niragi to join his plan to establish his utopia. After the Beach attracts more immigrants for food and leisure facilities, suicide, drug abuse, violence and sexual assault becomes more common. Hatter concludes that the Beach residents need an answer to fulfill their purpose by fabricating the false method of leaving the Borderland via collecting the complete suit of cards. The truth of his lie is only shared with Agni. As time has passed, Hatter is no longer able to differentiate his false hope from reality, he kills his residents for not offering their cards and amends the Beach rules for executing traitor.
Just 1 day before the Witch-Hunt game commences, Agni calls Hatter to an isolated bridge just outside of the Beach resort for bidding farewell because Hatter is no longer the person he once knew. Believing the departure is a grave treason, Hatter points his gun at Agni's head, but Agni reflexively shoots back and sends Hatter's body below the bridge. Agni quickly finds out Hatter's gun is not loaded and he actually desired death in his best friend's hand. Agni is devastated and decides to kill all Beach residents and himself during Witch-Hunt in order to bury their false hope for good.