Embereth Paladin
Creature — Human Knight
Haste
Adamant — If at least three red mana was spent to cast this spell, Embereth Paladin enters the battlefield with a +1/+1 counter on it.
"The king would die for the realm. I would not hesitate to do the same for him."
イラスト：
Throne of Eldraine#121コモン英語適正
裁定
If an effect allows you to cast a spell without paying its mana cost, you can’t choose to cast it and pay unless another rule or effect allows you to cast that spell for a cost. Similarly, you can’t waive a cost reduction unless that effect says you may.
Adamant effects check what mana was actually spent to cast a spell. If an effect allows you to spend mana “as though it were mana” of any color or type, that allows you to spend mana you couldn’t otherwise spend, but it doesn’t change what mana you spent to cast the spell.
If you copy a spell that has an adamant ability, no mana was spent to cast the copy at all, so that ability won’t apply.