Darting blow would nulify his weapon's ability as far as I know, because only the highest buff of the same type would be applied..but I might be wrong here, I haven't tried it myself. Fury is the safe bet in this case because it gives you enough stats to make him an all-round threat. After that, you can keep the rest of the build that you suggested.
From the simulations I did it does stack but Fury gives him more favorable matchups anyways. However if I want to make him even better in player phase LnD gives him even more favorable matchups at the cost of making him a lot more vulnerable in enemy phase so I'm not sure about that
Sorry for the mistake then. But anyway, I think that fury might be better because you are not going to lose his good defense stats. I feel that if you went with LND you would basically get a Lucina with a different weapon. Wifh fury you would even be able to bait hits and then just chain desperation kills, so you could ditch the suggested passive and go for a positioning skill like reposition.
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