User blog comment:IamJakuhoRaikoben/Chapter 459 & 460: Weakness & The Alighted Pegasus, Review./@comment-203.111.234.105-20151101162256/@comment-7418318-20151102075941

From the way Wahl analyzed Ichiya it's clear that he must have been aware of the IDSM, unless the whole tattoo-activated magic is an exception.