A grinning pink avali, Larry was a simple doodle drawn by Mauri Siru back when she was a part of the Nightwatch bounty hunting group. As one of the founders of the group, Mauri brought the design to Namiko as a logo for the Nightwach, Namiko then adopted the silly doodle as their mascot/logo. Mauri would refine the design into what we see today and Larry still remains the logo that's adorned on the Nightwatch's armor, even though the original creator has long since stepped away from the group.
Namiko does have a bit of a sentimental soul hidden under that trenchcoat of hers, after all.