Cavalier of Night
Creature — Elemental Knight
Lifelink
When Cavalier of Night enters the battlefield, you may sacrifice another creature. When you do, destroy target creature an opponent controls.
When Cavalier of Night dies, return target creature card with converted mana cost 3 or less from your graveyard to the battlefield.
イラスト：
Core Set 2020 Promos#94p神話レア英語適正
裁定
Cavalier of Night’s enters-the-battlefield ability goes on the stack without a target. While that ability is resolving, you may sacrifice another creature. When you do, the reflexive triggered ability triggers and you pick a target creature to be destroyed. This is different from effects that say “If you do . . .” in that players may take actions after you’ve sacrificed the creature but before the target creature is destroyed.
While resolving Cavalier of Night’s enters-the-battlefield ability, you can’t sacrifice more than one creature.
If a card in a graveyard has 
in its mana cost, X is considered to be 0.
If a creature card with converted mana cost 3 or less becomes a copy of Cavalier of Night, its last ability can target itself when it dies.