Hammann, a petite Sims-class Eagle Union destroyer, sports waist-length white hair tied in a ponytail, aqua eyes, and a black maid outfit accented with a red-and-black ribbon headdress. Her attire merges naval motifs with maid aesthetics: a white apron, American flag necktie, and red-and-white boots. Though her fake cat ears evoke Sakura Empire shipgirls, she maintains no direct ties to the faction.

Combining tsundere mannerisms with a sharp tongue, she frequently rebukes the commander as a “pervert,” masking her loyalty beneath abrasive banter. This protectiveness mirrors her historical defense of the USS Yorktown at Midway, channeled into skills like "Flagship Cover," which slashes flagship damage by 25%, and "Anti-Air Mode," trading firepower for enhanced air defense—a nod to her Coral Sea and Midway engagements.

As a secretary, she grumbles about workload yet covertly craves praise, rehearsing clumsy apologies after outbursts. These attempts often spiral into comedy, prompting her to recruit Yorktown for social guidance. Her trauma from sinking at Midway fuels a fierce drive to shield allies, sparking clashes with I-168, whom she holds responsible for her demise. Despite grudges, she collaborates in joint operations, whether managing food stalls with Ning Hai and Ping Hai or combating Sirens.

Gradual growth softens her prickly exterior: she begrudgingly acknowledges reliance on Sims and Yorktown, and her retrofit deepens her commitment to maid duties without dulling her edge. This arc reveals a resolve to balance pride with vulnerability, honoring her past while navigating camaraderie’s complexities.