Usunoro holds the title of Shinuchi (Headliner) in the Armored Division, the unit of Gifters commanded by Sasaki, though almost nothing about what he actually did during the war for Wano has made it into the story.
Nothing about Usunoro's actual look has been drawn or described. Since he's a Gifter in the Armored Division, he probably carries traits from a heavily armored Smile Fruit animal - a rhino or beetle type would fit the unit's theme - and likely wears the same reinforced armor or standard uniform as the rest of Sasaki's forces.
No dialogue or personality beats exist for him in the manga. Based on his rank and unit, he presumably shares the aggressive, hierarchy-driven mindset common among the Gifters.
Nothing is known about his family, origin, or childhood. At some point he ate an artificial Smile Fruit, which pushed him up to Shinuchi rank and got him placed in Sasaki's Armored Division.
Defense of Onigashima
Usunoro helped defend Onigashima during the invasion by the Ninja-Pirate-Mink-Samurai Alliance, stationed among the forces sent to stop intruders as they moved through the castle. His division fought during the standoff in the Skull Dome, trying to grab Kozuki Momonosuke away from Franky and Shinobu.
Like other Gifters, Usunoro was modified with an animal's Bloodline Elements, giving him strength and durability beyond a normal human. The Armored Division's reinforced builds make its members tough to hurt with ordinary attacks, and as a Shinuchi he outranks the Pleasures and Waiters below him. His intelligence is unknown. Like all Smile users, he can't swim and has lost the ability to feel sorrow or anger.
vs. Ninja-Pirate-Mink-Samurai Alliance — Ch. 996
The Armored Division tried to capture Momonosuke and clashed with Franky and Shinobu, scattering as the fight escalated - part of the larger push to wipe out the Kozuki bloodline.
No major or minor appearances have been indexed for him specifically; what's known comes from the Armored Division's role in Chapter 996.
No dialogue has been recorded for him.
His name, Usunoro (うすのろ), means "blockhead" or "slow-witted" in Japanese - a fitting label for one of the many disposable-sounding names given to minor Animal Kingdom Pirates. He's one of the Gifters that make up the artificial army Kaido and Caesar Clown built together.