We can't link N and Lucy but we can link the Advesary in its self same role. Like its a broad term and nonspecific but it's still a denomination af a specific thing. Other times in DF it's been said of things as 'their adversary'. A way to specify it as apposite to a specific thing. By calling it THE adversary you note a specific thing applied across a broad whole. E.g. Hannible was the adversary of Rome, he could have been called as much and it fits, later(iirc) Spartacus became Romes most notorious adversary. And since he's fulfilling the same role, Romans calling him the adversary makes sense. Lucy was the adversary, now literally everything seems to be stalked as Lea put it by the same 'adversary' so regardless it's filling th same role even if it's not quite the same. Same mantle different human memory attached to it.