Sweet! Hmm...the sixth is wrong?
Hmm...we need clues!
I'm gonna follow other people, and that is to break the paragraphs into chunks. I was also a bit skeptical over the deck idea, but it seems WPM finds no problem with it.
"reclaiming what they mislaid to our home a time ago"
Ok this is more of guessing than inference, but, reclaiming is to reuse, or reform. So, if it is a deck, then it was a deck that traveled to America a while back, then the Americans started using it, and now the Japanese are using this old deck again.
For the reforming definition then, it would mean that it was a deck idea that they leaked out, and then are now tweaking it and using it.
For the mislaid term, it could mean that the deck was accidentally leaked out at Worlds, or that they discussed at the event before forgetting about it, only now to revisit the idea again.
"The sixth one, in complete strategic alignment with the firedrake and bastet of no color, or, to a more destructive degree, in the exclusive solitude of only its own kind."
Looking at it again, it means that the the sixth is more dangerous with its own kind. I'm gonna take a wild guess and say that it means that this deck can be a mono deck. So it has variants, one with the firedrake and bastet, and with its own kind(line).