User blog comment:RoyalGuard-Elite/Isshin's Shikai/@comment-10371091-20131014121502

In my opinion, energy that can burn and slice through your surroundings is a bit cooler than fire, holy or not. Plus, it would make sense because Ichigo's powers are very similar as to bursts of energy in a mass quantity, and I also think that Kubo is more creative than suddenly running out of sword ideas and decides to just recycle powers such as fire: the most common in anime. Or maybe it's not fire, but a different combination of elements??