Hatsune Miku was originally a voice synthesizer program that became so popular that she became a cultural icon in Japan. She’s in video games like Project Diva and was recently added as a dlc character in Crypt of the Necrodancer, she’s appeared in commercials and is the mascot of a racing team. There are too many fanworks, songs, animations, miku finds a pipebomb for example, to count. It all started as a program, but then turned into a whole lot more than that.