Soulcipher Board
Artifact
This artifact enters with three omen counters on it.
, 
: Look at the top two cards of your library. Put one of them into your graveyard.
Whenever a creature card is put into your graveyard from anywhere, remove an omen counter from this artifact. Then if it has no omen counters on it, transform it.
Cipherbound Spirit
.
Creature — SpiritFlying
This creature can block only creatures with flying.
: Draw two cards, then discard a card.
Rather than consort with demons, the Quietus Cult seeks wisdom from the dead.
Caio Monteiro
Rulings
Soulcipher Board's last ability triggers when a creature card is put into a graveyard from anywhere. This is different than an ability that triggers when a creature dies. Notably, a noncreature card on the battlefield that becomes a creature and dies (such as an animated land) won't cause this ability to trigger. Similarly, a creature card on the battlefield that has been made a noncreature permanent (such as one enchanted with Minimus Containment) will cause this ability to trigger when that card is put into your graveyard.
(wotc • 2021-11-19)
Token creatures dying never cause Soulcipher Board's last ability to trigger.
(wotc • 2021-11-19)
Rulings
Soulcipher Board's last ability triggers when a creature card is put into a graveyard from anywhere. This is different than an ability that triggers when a creature dies. Notably, a noncreature card on the battlefield that becomes a creature and dies (such as an animated land) won't cause this ability to trigger. Similarly, a creature card on the battlefield that has been made a noncreature permanent (such as one enchanted with Minimus Containment) will cause this ability to trigger when that card is put into your graveyard.
(wotc • 2021-11-19)
Token creatures dying never cause Soulcipher Board's last ability to trigger.
(wotc • 2021-11-19)