Sword is a turn delay thatyou ideally dump with Shooting Riser. It gives you a level 8 synchro or a Needlefiber all by itself, or it gives you a level 6 and a pop. The two are similar in appearance alone, while acting completely different in actual play, seeing as a useless single sohaya is all Vayu gets you.
Even then, Sword is a 1-of tech choice, and more and more I think it’s not really worth it, so...
Not to mention that, should push come to shove, zombies have a lot of ways to put Sword in grave or get it from deck. Blackwings have precisely Needlefiber to fill that function, meaning it will likely consume your NS for a bad cardthat only does Sohaya.
This isn’t me being overly dismissive. This is hyping up a card that wastes an ED slot for a level 5 synchro that offers nothing on its own, especially since you won’t be summoning or running more than 1 Sohaya, so it isn’t worth it. And Vayu isn’t even the topic.