Osomatsu (voiced in Japanese by Takahiro Sakurai and in English by Billy Kametz) is the titular character of the Osomatsu-san anime.

He is the oldest brother out of all of the Matsuno sextuplets and likes to use that to his advantage to put himself as the leader in most situations. He shares a fair amount of basic traits with his brothers, as he's somewhat meant to be the standard they're all based around, so while the others are very prominent in what they are into and act like, he doesn't stand out as much of a character in comparison.

Oso has the same short dark hair as the others, with matching eyes. Like his brothers he also wears the same kind of hoodie, with his being red, and he is the one most often seen in that while the others change their fashions around more frequently. He wears the same kind of pants as the rest of them, white crew socks, and red slip on shoes.

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