He is a short man, with long wavy gray hair. He has tattoos of his number on each side of his face, and a large black top hat. He wears a dark blue coat with a gray collar and yellow buttons. Underneath, he sports a purple puffy shirt and black pants.
He unwittingly gave out information about Baroque Works, so it seems he cannot keep a secret very well. Mr. 11 also seems to be quite easy to trick, as shown as how Smoker tricked him into revealing Baroque Work's secret (such as making him believe they found a particular letter in his pocket, which they never found). He also mistook a group of Billions agents for Millions agents, showing he does not know much about the lower members of his organization, or the members on his level for that matter.
Abilities and Powers
He was not seen fighting, but, as a Frontier Agent he must be somewhat proficient in fighting and bounty hunting.
Since he had a sword, it's likely he was decent swordfighter, though not on par with Tashigi.
When an unforeseen event happened that caused the crew, including Smoker, to leave their ship, Mr. 11 attempted to free himself. Surprisingly, Billions agents (henchmen for Officer Agents) boarded the ship. Mr. 11, mistaking them for Millions (henchmen for Frontier Agents), yelled at them to untie him. The Billions then revealed their rank and were hence the same level as him (agents below rank 10 are not much stronger than the Billions).
Mr. 11 then apologized, but it was a little too late, as they had no intention of freeing him. Mr. Mellow came toward Mr. 11 and shot him. Though his death is not shown, Mr. Mellow's comment and Tashigi telling Smoker he was murdered confirms it.