The starter deck is packed with Items, Actions, and Songs that will help your deck achieve what it was designed to do
Food artifact with ", , Sacrifice this token: You gain 3 life" (FFXV) for Ignis Scientia and Sidequest: Catch a Fish
This all culminates in an ending where Yuna's whistling to try and desperately reach out to a Tidus who's not there, which in turn results in a post-credits scene where, well, play the game for yourself
Functionally, what this effect says is that if you can attack with The Lord Master of Hell, and you have 40 or more cards in your graveyard that are neither creatures nor lands, you win the game
For Yshtola, it came down to a mix of popularity of the character as well as being a spellcaster, her story and character development offered a wide range of abilities and moments to pull from to lead the deck
What does the future really hold for Masters sets, and what do the big moves from Wizards over the last couple of weeks really mean