Overdrive (オーバードライブ)/theories

323 is Alien
323 has effects such as Cyber Costume and Laser Gun, which are suspicious for a young girl to have, probably intimating that she isn't really a human. Another proof is her unorthodox name. 323's real name might be impossible to pronounce in human language so researchers might gave her number 323 instead. Also her taking UFO and flying away in True End (aka END 3) might also prove that 323 is an alien.