How do I stop this thing? I'm a thinker, not a fighter! Think...think...

–Hiro's quote.

Hiro Watanabe (渡辺博) is a 10 year old 5th grade student who becomes Grey Matter with his Grey Matter DISK. His Exo-Hero code is X-5.

Form, Powers, and Abilities

Exodus Grey Matter

Accepted. Materializing: Galvan Identity.

–Grey Matter DISK's transformation announcement

Grey Matter! Disk Mash!

–Hiro's transformation announcement

Exodus Grey Matter.

As Grey Matter, Hiro's small size belies his great calculative and technical intellect. He can create complicated machines from spare parts, understand the function of any device at a glance, and make sophisticated repairs to complex machines (such as a warp-drive engine).

Hiro's intellect serves as a problem solver and analytical help in difficult situations. This allows him to think more strategically when brute force is inefficient. In fact, Grey Matter is smart enough to know how to unlock the original Omnitrix's Master Control.

Hiro's brain capacity makes Ben smarter about things he has never even seen before.

Hiro can sometimes manipulate living things by stimulating certain parts of their nervous system if such beings can be controlled by external stimuli.

Hiro's size allows him to squeeze into small spaces and can climb walls due to microscopic pads on his skin. He also has sharp teeth that can cause pain to those he bites, as well as slimy skin that makes him difficult to grab.

Hiro was the weakest alien in this series due to his minuscule size, but he compensates with his intellect and efficient technological and calculative skills.

Hiro's intelligence is not limited to technology and biology, as he is smart in general. Even if he does not know something, he can learn it very quickly.

Hiro appears to be stronger than he looks.

Hiro can breathe underwater due to having gills, making him amphibious.

Hiro has a long prehensile tongue, owing to his insectivore nature.


Hiro's small size makes him unsuitable for physical battle, so he must outsmart his enemies in a fight. Animals like dogs and cats can be a problem, as they may see him as a chew toy or food to them.

Despite possessing immense intelligence, Hiro can still make miscalculations.

According to himself, Hiro sometimes does not know what he is talking about.

Hiro does not know everything, as seen when he (initially) did not know which galaxy his species is from.

Being a Galvan, Hiro would be vulnerable to being trapped by a member of Omnivoracious's species if they were not extinct.

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