Event Chaos Arena

Three years after Igawa Asagi defeated the Oboro Ninja Troops and killed the leader Oboro, she retired.

However, Asagi was informed by the Taimanin Senior, that new murders had begun and Oboro had returned. In Taimanin Asagi, Asagi was captured with her boyfriend Sawaki Kyousuke and her sister Igawa Sakura.

Forced to fight in an underground fighting ring called the "Chaos Arena" under control of Oboro and Nomad. Asagi was able to free herself and her sister however, Asagi was forced to kill Kyousuke, which was used as a host for Oboro at the time.

These events are canon in all games after Taimanin Asagi.

The Chaos Arena was rebuild after this multiple times at other locations.