I have come a ways and have made good progress on my custom archetype based on serpent night dragon seiyaryu called the serpent knights. The 2 major main deck monsters aside from their dragon forms will be the original human incarnations of seiyaryu and serpent night dragon. I did change the story behind them a bit as well. The two knights were both comrades in arms and lovers, however the holy serpent knight (Seiyaryu) fell in battle which drove her lover the shadowy serpent knight (Serpent night dragon) to despair and darkness, which eventually caused his transformation. The gods of light soon decided to resurrect and transform the holy knight into a being capable of combating this new threat, while neglecting to tell the newly born seiyaryu the serpent night dragon's true identity.
I will eventually post some of the cards on my gallery if you are interested.