Note that's Shadan's nightfall text is static, so Zax's answer is right for him. If it's not the first turn, the text is in effect.
Whereas guys like Pravian
do need to come into play in the first turn to get their daybreak react, or after that to get the nightfall one.
It's one of the few true downsides to the "no reacts before the first turn" rule and Jautya Syne
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