Living End is a blue-adjacent combo deck relying on Force of Negation and Shardless Agent (blue spells), making Mystical Dispute a cheap, one-mana counter to protect our own graveyard plan and stop theirs. Subtlety can flash in to put an opposing creature spell on the top or bottom of their library, answering a key Shardless Agent before Living End resolves, and its evoke mode is relevant if we need free interaction. Since both decks want their graveyard intact, avoid boarding in graveyard hate that would hurt our own Griselbrand/Atraxa plan. Faithful Mending is too slow in this fast combo mirror where speed and disruption matter most.