Herman is a tall man who has white slicked-back hair with a part of his hair falling from his forehead. He has gray eyes and a full beard and mustache. He typically wears a cream-colored long-sleeved shirt with a matching-colored puff tie that had a whale design on its end. Additionally, he wore a brown vest that had black accents, on whose left breast pocket is a white pocket square. He also wore a pair of black pants and shoes. He is rarely seen without his wooden pipe, and he occasionally carries with him a black jacket.
In his younger years, his hair was still slicked back, albeit most of his hair dropped down on from his left forehead to his cheek. He also had a shorter beard and a slight goatee. He wore a pinstriped three-quarter-sleeved shirt and suspenders tied to a pair of light-colored pants, as well as a pair of Oxfords.
Herman is a generally reserved and quiet person, though he is implied to have been a competent leader as a former head of the Guild. He is shown to be a loyal member of the organization, as well as a devoted "captain" to his ship, Moby Dick. Because of the years he spent together with it, Herman dearly considers Moby Dick as his old friend and describes it to be "very beautiful" before being mechanized by the Guild. Hence, even in the face of imminent crashing during the Guild's emergency plan, Herman decided to stay with Moby Dick, opting to go down with it in its possible final moments.
Herman's ability, Moby Dick (
It is indicated that Herman's ability also involves creating volant white whales instead of simply controlling them. This is seen when Ango Sakaguchi takes Herman to interrogate him regarding the Guild, and a white whale similar to Moby Dick (though much smaller in scale) was left on the bench he sat on.
It is stated by Ango that Herman is one of the first members to join the Guild when the organization was in its prime, being described by him as "beautiful". It is later mentioned that Herman was actually the Guild's leader two generations before Francis Scott Key Fitzgerald's leadership.
Herman first appears along with the other Guild members when they interrupt the fight between Kōyō Ozaki and Atsushi Nakajima.. He later accompanies Fitzgerald as they capture Atsushi, later summoning Moby Dick to escape.
In the wake of the Guild's emergency plan, Atsushi encounters Herman while looking for the control terminal on Moby Dick. As Atsushi wonders why the airship seems to be deserted, Herman informs Atsushi that everyone has fled Moby Dick in preparation for their plan of crashing the aircraft to Yokohama. He also tells Atsushi where the terminal is located. Eventually, Herman reminisces on the past grandeur of Moby Dick before getting mechanized by the Guild; he asserts that the least he can do for the danger that Moby Dick would befall the populace is to go down with it.
After Fitzgerald's defeat, Atsushi and Ryunosuke Akutagawa manage to take the control terminal to stop Moby Dick's descent, but Herman later tells them that someone from the outside has seized control over Moby Dick, and there is no use to try to stop it. In the end, as Herman, Atsushi, and Akutagawa flee the ship, Kyōka Izumi crashes the unmanned aircraft she is imprisoned in into Moby Dick, which results to the sinking of the aerial fortress in Yokohama waters. In the aftermath, Herman is approached by Ango and persuades him into coming with him for interrogation. Though initially hesitant and doubtful that he would not be of much help, Herman eventually decides to go with Ango.