What exactly is ? It is not a traditional film studio. It is not a standard fashion house. Instead, Studio 13 (the "tas 5599" likely serves as a batch code, artist signature, or archival reference—a nod to analog recording systems) is a hybrid creative collective. Founded in the late 2010s but gaining cult status only recently, Studio 13 operates on the fringe of mainstream Hollywood and high fashion.
However, I need to clarify that the topic you've provided seems to be quite specific and related to a particular studio or creative work. After conducting a search, I found that "Eternal Nymphets" and "Eternal Aphrodites" might be related to a Japanese visual novel or anime-style project, but I couldn't find much information on it.