Norton Fighter is a promotional character for Symantec Japan. Originally intended for a product launch event in September his role continues to expand as he helps promote Symantec Internet Security and defend the Internet from a wide array of Security Threats.
Here is a video from the inital event in Akihabara
Then there was the now famous instore battle between Norton Fighter and the Virus Soldiers.
Check out more pictures from the event at Yodobashi Camera and subsequent guerilla walk about through Shibuya here