Doomed Necromancer and Apprentice Necromancer I'm putting these both together because of just how similar they are
These legends enable and often are a payoff to whatever your deck wants to be doing or let you cheat on costs or some other benefit that might be innate to the type of card youre using
Eventually, with five plan counters, it exiles the top five cards of an opponent's library and casts two spells from that stack without paying the mana cost
If it's a Siege, it will still be exiled when the last defense counter is removed from it, and its controller may still cast it transformed without paying its mana cost
And I simply can't cast them
Without a specific combo to play toward, all the face-down trickery is either generating value to help us dominate the board or providing some instant speed utility so we arent complete, sitting ducks for every blue player at the table