To be considered, one must pull the Z Sword from it's resting place.
To do so, one needs to be pure of heart, and have sufficient strength to do so.
After all of this, the next step is to meditate with Rou Dai KaioShin. After 10 days of intense mediation(where you recieve no points) the transformation is possible.
Mystic Transformation
Requirements-see above- (Stats x15)