Hercules
There is no specific myth or reasoning behind the use of the number 12 on mythology aside from it's connection to the calendar and the zodiac. The only instances of 12 are the 12 Olympians and the 12 labors of Heracles (which were originally 10)
To perform his 12 labors.
Heracles (Greek) Hercules (Roman) had to complete 12 labors.
According to Greek mythology, Hippolyta was the queen of the Amazons - who were women warriors. She mainly shows up in the mythology in relation to Hercules/Heracles getting her girdle (a gift from her father, the God Ares) as the ninth of his 12 labors and in a variety of myths that had her married to Theseus.
Hercules
Hercules
Perseus. Bellerophon killed the Chimera, Theseus killed the Minotaur, and Heracles completed the 12 labors.
By carrying out his 12 labors.
Herakles AKA Hercules.
Hercules because he wanted to
Hercules did it for for Hera
To redeem himself for the murder of his wife and children.