He was believed by many fans to have been originally created as a NESTS experiment, mainly a clone of Kusanagi Kyou, due to a special intro he has with K9999. This introduction is, in fact, an homage to AKIRA as both K9999 and Kusanagi have the same voice actors as Tetsuo and Kaneda respectively.
His actual backstory in KOF 2003 reveals him to be a product of Kagura Chizuru's magic, used to test the strength of the tournament's contestants. His evil appearance is possibly due to the fact that he was created by Chizuru while under the control of Mukai (the leader of the KOF 2003 operation) and Botan (the puppeteer controlling Chizuru).
