Demon's Disciple

• WWizards of the Coast2020-09-25
  Official Ruling
  As the triggered ability resolves, first the player whose turn it is chooses a creature or planeswalker they control, then each other player in turn order does the same, knowing the choices made before them. Then all the chosen creatures and/or planeswalkers are sacrificed at the same time.
• WWizards of the Coast2020-09-25
  Official Ruling
  Demon's Disciple can be the creature sacrificed for its own ability.

Rulings via Scryfall