Daemon Spade is a villain from Katekyo Hitman Reborn!. He is the true orchestrator of the long-standing feud between the Vongola Family and the Simon Family.
Daemon was born into a wealthy, noble family, but he grew to despise people who lived affluent, easy lives. Daemon met a woman named Elena who shared his views and the two of them fell in love. Elena introduced Daemon to Giotto, the the founder of the Vongola Family. Daemon became a loyal member of the family under Giotto, earning the title of "Mist Guardian." He also garnered a reputation as a powerful illusionist.
Some time later, Elena was murdered by a rival Family. Daemon's personality changed from kind to very manipulative, and he became distrustful.
Out of spite for Elena's murderers, Daemon began to kill those he saw as weak. He kept his killings a secret from Giotto. Daemon then tried to kill a good friend of Giotto's, whom Daemon thought was a coward. After failing to kill the man, Daemon defected from Giotto, claiming that the boss had become "soft." Daemon forced Giotto to resign, while he and the other Guardians kept their positions. Power shifted from Giotto to his successor, Ricardo.
Seven years before the present time, Daemon killed 12 loyal members of the Vongola Family and used his illusionary powers to disguise himself as Iemitsu Sawada, the father of Tsuna Sawada. Disguised as Iemitsu, Daemon killed the family of Enma Kozato, a member of the Simon Family. This led to Enma to hate the Vongola, and Iemitsu in particular.
In the storyline, Daemon first appears as a spectre to the 10th Generation Vongola Family, whom he deems to be "unworthy" of continuing the Vongola name. He puts them through a difficult trial that tests their strength, and they are ultimately able to overcome it. Daemon half-heartedly gives the 10th Generation Family his approval before disappearing. He was the last of the 1st Generation Guardians to give the 10th Generation his approval.
Some time before the Simon Family declare war on the Vongola Family, Daemon possesses a member of the Simon Family named Julie Katou.
Later on, after the Simon Family declare war on the Vongola Family, Daemon revealed his plan to possess Mukuro Rokudo, the 10th Generation Mist Guardian and himself a powerful illusionist. The two of them fought with Daemon managing to take over Mukuro's body. Even thought he put a very difficult fight he was eventually defeated by Tsuna. As he lay dying, Daemon explained to Tsuna his past and why he had staged the war between the Vongola and the Simon. Daemon asks for Elena's forgiveness which leads to him accepting Tsuna and the others to take care of the family. Before he moves on, Daemon tells Tsuna to maintain the family name or else he will not forgive him. Daemon then fades away peacefully.
Daemon was a very powerful illusionist and capable of possessing others with little resistance from them. Other powers he demonstrated included teleportation, mind control, and the ability to heal his wounds. He was shown to be very intelligent and a skilled fighter, though he preferred using illusions to fight.