Yusei and Akiza's relationships in fan-fics. Named so because before Yusei and Aki got to know each other well, they trusted the other because of the Crimson Dragon and put their faith in one another to defeat the Dark Signers.
Yu-Gi-Oh! 5D's Lion King - Aki and Leo were friends when they were young until he ran away and changed his name to Yusei. They found each other again and their frienship grew into love. After he defeats Roman, he takes the throne with Aki and they have a child.
YGO 5D's-New Domino Girls - Akiza is Yusei's counterpart in this fanfic song