Final answer:
The '5Ds' in Yu-Gi-Oh! 5Ds stands for Destiny, Duel, Duelist, Dragon, and Darkness, which are attributes represented by the main characters. The members of this group, known as Signers, are Yusei Fudo, Jack Atlas, Akiza Izinski, Crow Hogan, and Leo and Luna.
Step-by-step explanation:
In Yu-Gi-Oh! 5Ds, the '5Ds' stands for the five different attributes represented among the main protagonists, which are Destiny, Duel, Duelist, Dragon, and Darkness. The characters that are members of this group each have a dragon-type 'Signer Dragon' card that reflects one of these attributes. The main members of this group include Yusei Fudo, Jack Atlas, Akiza Izinski, Crow Hogan, and Leo and Luna (who share a dragon). These characters are known collectively as the Signers, who are chosen by the Crimson Dragon and have special marks that set them apart from other duelists.