Tsuna and Enma's rings combine, forming a new Ring, which turned out to be the seventh and last key of Giotto and Simon Cozzato's history. It revealed that once both Vongola and Simon in the future once again return to their true friendship after the conflict, if they prove to honor the oath, their will will become one and both Giotto and Cozzato's Flames within their rings would burn. After witnessing the seventh key, the enraged Demon Spade attacked again as he angrily shouts that Giotto and Cozzato were only dead people that interfered; however, as he attacks, he finds Tsuna already recovered thanks to Enma's Earth Flame's Gravity manipulation, which he used to mend and hold his bones in place. Tsuna then tells Demon that both of them are alive within the ring's Flames.
Suddenly, Tsuna manages to overpower Demon and critically injure him with his X-Burner; however, Tsuna knew that the Flames weren't enough to defeat him. Demon quickly healed his entire body as he cursed Tsuna, revealing monster mouths and eyes throughout his body. Tsuna stated that the Flames he will use to defeat him wouldn't be Giotto and Cozzato's Flames, but his and Enma's. As they prepare to trade one final blow, Jaeger and Reborn both comment that that attack would be the end.
Note:Bold + Italicized = First Appearance