General guidelines of sideboarding and how sideboards are constructed is a topic I try to come back to periodically because I think there are a lot of really general rules that extend to most formats and circumstances that I think arent widely understood
Invented to symbolize the Werewolves in original Innistrad changing from Humans to wolf-monsters and back again, the cards represented a massive leap into previously unexplored design space
The good news, however, is that this card may be a depiction of their marriage in the afterlife, something hinted at by the ending of Final Fantasy 15 and confirmed in the now-defunct mobile game, Dissidia Opera Omnia
Just 20 copies of this card were given to the winner, and they seemingly disappeared off the face of the earth
Its hard to quantify an answer to that question, but Id guess that Gray Merchant of Asphodel is in the top five black game-enders ever
Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)