” Power… Speed… They
mean nothing to me…”
Hana-Hana referred to the length of an arm. Robin’s height is 188 cm. her arm length is approximately 100 centimeters / 1 meter. So to calculate simply : 100 x 200 = 20.000. 20 kilometers. That’s the radius of Robin’s power. To put simply and not making her over powered, the radius is 10 kilometers in round-shape radius around her vicinity.
So as long as she has her radius, she can apply as many limbs as she wishes in “200 hana-hana away.” This speculation is further emphasized by Buggy’s 200 bara-bara. In radius of Buggy’s legs on land, he can separate & levitate his body in exact radius for his power to be effective.
So it means although that Robin can sprout limbs in designated area as she wishes, she cannot sprout her limbs outside 200 hana-hana radius. To put simply for example: Robin can sprout half of her body in quite a distance to inform Law, but that’s because Dressrosa island is probably less than 10 km width. Robin definitely know exactly Alabasta, but of course she can’t sprout her limbs on Alabasta because it’s not within her radius of Hana-Hana.
So as long as it’s within the radius of 200 Hana-Hana, Robin can sprout even thousands of limbs and her entire body in the Hana-Hana radius. Not to mention that Robin needs to know the object / place her body need to be sprouted; as it was once with the South Bird where she needs to see one to catch a South Bird; because if she doesn’t know the exact object where she will sprout her limbs, she can’t sprout her body. That’s why Robin can probably have photographic memory as well, because when she sprouted half of her body to appear beside Law, she needed to memorized the Green Bit area.
And of course it explains Robin’s “limitations”, because if she can sprout her limbs on any surface as she wants without the limited radius, she will be overpowered. Not just Robin, but probably Luffy has 200 Gomu-Gomu away where he can elongate his body on a max length. This 200 Hana-Hana is another “weakness” of Robin’s power to make her less overpowered, as “power and speed mean nothing to her.”
And there is a question why Robin can sprout her limbs on organic matter (like on human body), but she can’t sprout her limbs inside an enemy’s body. The logical reason is probably because as Robin’s power is Hana-Hana, an enemy’s inside body doesn’t have enough room for her limbs to grow. Another reason is because although at first Robin’s specialty is assassination, after she joins the Straw Hat Pirates, she omitted assassination as her specialty probably because it is considered too brutal & against the crew’s moral code to kill someone.
This could be possible that in the future, Straw Hat Pirates will probably have a messenger as well, the way how Black Beard’s Laffitte is also a messenger. This messenger will connect between the Straw Hat grand fleet, because Robin can’t sprout herself more than 200 hana-hana away. So the same like Laffitte, this messenger will have the ability to fly as well & easily infiltrate any place.*Theory by DevilChild93