This card and the characters it portrays are
another storyline payoff from years past - these
two are sibling necromancers who were mentioned
in various flavor text from the original
Innistrad block, often with a witty remark to
make about each other or the uptight knights who
fought against them. It looks like they're not
going to be this generation's Urza and Mishra,
having learned to work together and enable the
delirium mechanic and any kind of
graveyard-related play ranging from the obvious
ones to Unburial Rites and Conflagrate. Zombie
tribal decks have traditionally not had much of
a problem recurring creatures, but another
option is always welcome, and it gets especially
ridiculous in Commander, where the siblings
themselves are harder to permanently shut down
than in conventional decks.
Everyone's favorite
stitcher and ghoulcaller siblings have returned,
trying to be a good centerpiece for a deck
centered around the undead. And their abilities
aren't bad: load up the yard, then start casting
things out of it.
The issue is that they are,
in practice, a bit underwhelming. They're out of
burn range, but it's not practical to expect to
start casting things on the turn they drop,
leaving them exposed for that first turn.
They're too slow and fiddly to make in
constructed, but they can definitely undeath it
up in more laid-back formats.