Stuka functions as both watchdog and support companion to Nanoca Flanka, joining her upon her arrival in Tristia. He is an artificial creature, not a natural animal. Alongside the golem Tenzan, Stuka assists Nanoca in her daily activities and is frequently present within her workshop environment. During workshop scenes, he is often depicted lying near Nanoca while she invents, underscoring his constant companionship. Despite his canine form, Stuka possesses the ability to communicate verbally, expressing his thoughts using a deep male voice. His role extends beyond that of a typical animal companion, as he functions as an active participant in interactions through dialogue.