I have a theory that the kidnapper is Wano is the Zero of the Numbers and will be in a way a Vegapunk satellite.
I think Zero is the silhouette Number that appeared in the Vegapunk's flashback with Clover. A new dragon was revealed which I think hints that there is a new number.
I think there is precedent, number themed groups usually have a 0 member. Kuma who Vegapunk turned into a cyborg was PX-0.
I think Zero will look like Yamato's hannya mask for a couple of reasons.
The kidnapper is primarily targeting women.
Which I think is connected to Oden's past when he kidnapped women to create his own personal harem. Sukiyaki compared him to a yokai.
I think it will follow the pattern of monster looking characters describing other characters with their own features,
Big Mom stated that the Numbers are failures. It hasn't been relayed why but a popular theory is that it's because they have low intelligence.
I think Vegapunk came up with a solution to use his own blood to augment the Numbers to pass on his intelligence. I think he tried it on Zero and thought it was a failure but was wrong. Hannya is Japanese for Prajñā which means wisdom which is why I think Zero will look like a hannya and a hint he is intelligent.
As to why he is not a giant I think he came up with a method to shrink similar to Vegapunk creating medicine for the Punk Hazard kids.
I think there has been hints. Usopp comedically asked if he was Vegapunk when he found out about the Satellites which I think is a hint there is one more.
Luffy called Vegapunk a ninja when he find out he cloned himself which I think is a hint he has a clone in Wano.
In Wano Orochi told CP-0 it would cost them Vegapunk fort the next shipment of weapons.
Orochi could grow seven heads which I think is a hint at a 7th Vegapunk.
Vegapunk's technology that allows objects to eat Devil Fruits appeared in Wano. Somehow Sukiyaki got ahold of it.
Vegapunk knew that a second dragon appeared in Wano which I think hints at that Zero was in communication with him. It doesn't really make sense for the WG to keep Vegapunk in the loop since they were going to kill him.
I think Zero created the Marys. They use cyborg animals which is a hallmark of Vegapunk. Their eye masks seem like they are inspired by Who's-Who.
It reminds of Vegapunk basing and naming the Pacifistas after Kuma. Who's-Who and Kuma have things in common. Both were victims of the World Government and idolized Nika.
I think Zero perfected Orochi's Horse Gifters. They look normal which is uncommon for the Gifters.
I think the end of Yamato's cover story will be Zero healing the victims of failed SMILE which I think the Horse Giters allude to.
