Must be Fusion Summoned and cannot be Special Summoned by other ways.
The ?? - Hex-Sealed Fusion doesn't work with most elemental hero. Another mislead tips, gameA don't know how to play with fusion deck.
GameA is not a single person. GameA runs by multiple "humans" without taking money from your pocket. And "humans" do mistake sometimes. It's called "human mistake". Be forgiving or leave and create your own website. At least most of other info they have is right
Interestingly, it seems someone at Gamea struggles to understand what Sealed Hex cards actually do. This is not the first time an article suggest to use Sealed Hex despite the Sealed Hex being unable to be used in the way the article suggested.