User blog comment:IamJakuhoRaikoben/Chapter 473: Red Lightning, Review./@comment-1776824-20160216185112/@comment-1839664-20160216223728

As some of you should know, there are a lot of ways to say thunder/lightning in Japanese. Ikazuchi (いかずち) is one of them. One of the way to pronounce the kanji 御 is 'Mi'. So put the two together, and you get Mikazuchi (御雷).

If you guys want to understand further, the part on "Mikazuchi" is most likely based from the Lightning God, Takemikazuchi.