Cold as the Sun is influenced, stylistically, by salsa music in the percussion writing, and rumba flamenca and other JRPG themes in the guitar. Actually, Steady as a Gun was written first, so the chord progression is taken from that, as opposed to mariachi progressions which seem like they traditionally use combinations of I, IV, and V. But I suppose we can say that the bVI to V7 here has similarities to an Andalusian cadence in flamenco! The chord progressions and scales used on this soundtrack are a bit of a fusion of what is traditional and nontraditional since I just like exploring cool progressions way too much.