According to Kotaku, Hareruya made its name with the Magic The Gathering TCG, and began life in 2009 selling cards for that game
Some forces have pushed constructed Magic towards greater consistency, including, but not limited to, the mulligan rules (and especially the London mulligan), the massively expanded card pool with many functional variants or copies of existing cards, and the greater efficiency of deck manipulation (especially with the advent of cantrips and fetchlands)
"If we ever were to return to Kamigawa, we might use Ninjutsu since that's where it was developed and it is iconic to that," senior game designer Eric Engelhard tells Polygon
deck.): If your opponent has 7 or more cards in their hand, trash 2 cards from your opponent's hand
Illustrated by Michael Komarck Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Legal Brawl Not Legal Legacy Legal Comp
These could very well be a mix of legendary creatures and other kinds of spells, but that remains to be seen