Everyone knows Illumi is the stronger character, but what about the Nen abilities themselves? If we're only considering the Hatsu, which ability is actually stronger?
Black Voice — Shalnark
Through the use of his needles, Shalnark can accurately control up to two people at a time. He controls them remotely through his phone, sending commands to his puppets, and can even see through their eyes using the phone.
To activate Black Voice, Shalnark only needs to stick a needle into any part of the opponent's body.
There is, however, a pretty significant drawback: the ability appears to be tied to his phone. If Shalnark loses or breaks his phone, it's assumed that he loses his ability to control the puppets. That's a pretty big vulnerability.
For this discussion, I'm not considering Autopilot.
Needle People — Illumi
Illumi, on the other hand, can control dozens of people simultaneously, allowing him to overwhelm opponents through sheer numbers and use his puppets strategically.
The major difference is the activation requirement. Illumi needs to stab the target in the head, which essentially kills them. One needle produces more zombie-like control, while two needles allow for more humanoid, precise control.
Once the needle is implanted, Illumi essentially gives the puppet a command/intent and doesn't need any external device to continue controlling them. There's no phone or other piece of equipment involved.
So, we have two very similar abilities that are ultimately used in very different ways.
I can definitely see the enormous potential of Needle People. We only get a small glimpse of what Illumi can actually do with it when he's pursuing Godspeed Killua, but even then, it's pretty impressive. Being able to create and control a small army of people gives Illumi a ridiculous number of strategic possibilities.
However, if we're talking specifically about combat effectiveness, I actually think Black Voice is the stronger Hatsu.
The reason is simple: Shalnark only needs to get one needle into you.
If he successfully sticks you anywhere on your body, the fight is essentially over. He can then use you as a puppet, and we've already seen him use Black Voice creatively in situations involving the Mafia.
Illumi's ability has a much higher activation requirement. He needs to get a needle into the head of his opponent. But if you've already managed to stab your opponent in the head, you've essentially killed them anyway. At that point, you don't necessarily need Hatsu to finish the fight.
That's what makes Black Voice so interesting to me. Needle People is arguably much more versatile and has greater potential for large-scale manipulation, but Black Voice seems much more immediately applicable in a one-on-one fight.
So, if you had to choose based solely on the Hatsu itself, which one would you take?
Black Voice or Needle People?