No, The Hidden Isle is its own standalone IP. Started with a board game, mutated into a Tarot deck and now becomes a TTRPG. Maybe we do a webcomic next ;)
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The deck was not made for the Hidden Isle specifically but for their first kickstarter board game Sefirot. Which is kind of a solitaire style tarot card/board game.
So while not made for this game specifically, the creators of the game also made the deck and the art styles are the same.
The deck is lovely and I followed its development from when the Sefirot kickstarter first launched.