Why is the daughter creature also Darkness? The daughter creature is supposed to be the original creature.
Also,
E.G. Put it on a life creature, the life creature is now affected by Nightfall/Eclipse & its ability is now 2
Mitosis, which will generate a darkness daughter creature that is in turn affected by mitosis.
Why does the ability specifically cost 2
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? Does the card cause the ability to automatically cost 2 rather than what you also said before (that it only changes quanta type, not quanta cost)?
Also also, if you don't have suitable art,
don't put in a copyrighted image. You don't
have to have an image; if you have one that is allowed then use it, if not, then don't.
EDIT: I'm assuming this also will work alongside Holy Light? (you didn't mention it specifically, only Nightfall, so unsure on whether or not that Nightfall synergy was the only intended effect)