The Devil Gene
The Devil Gene is a gene in the Mishima Family which affects Jin. Kazuya and Jinpachi but strangely doesn't affect Heihachi. Though is must be noted that Jinpachi's Devil transformation is not hereditary, his body was taken over by "This Thing" as he refers to it, whilst he was locked under the Hon-Maru. The gene affects Kazuya and Jin and makes them evil.
The Devil Gene versions of Jin and Kazuya are featured as playable characters within the series, known as Devil Jin and Devil (or Devil Kazuya). They play differently from their human forms. Jinpachi, however, plays the exact same in his human form.
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