Dark Yashiro is a Mirage that, through the effect of being within close proximity to a Dragonstone shard, was affected by a residual essence of Yashiro Tsurugi in his Carnage Form and transformed into his warped doppelganger. Believing himself to be the true Yashiro, he holds a concert in the Idolasphere, and Itsuki's party puts a stop to him in order to recover the piece of the Dragonstone in his possession.
Though they are physically near identical, Dark Yashiro's personality deviates from the real Yashiro's in a number of ways. One which Yashiro finds appalling in particular is Dark Yashiro's tendency to use words and phrases like "Ta-ta" in his speech, which the real Yashiro would never use.
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Subjective: The following part of this article is based upon the editor's personal experiences and opinions, and therefore may not be applicable for all readers.
Dark Yashiro features a unique trait in his boss battle, in that he can separate himself into multiple copies for several turns at a time before reverting to a single body. Early in the fight, he splits into two, but later, he is able to split into as many as four. If a duplicate is defeated, however, it will not regenerate the next time Yashiro copies himself.
- Dark Yashiro's status as Yashiro's imposter, as well as his general color scheme, is reference to other imposters of famous sword fighters, such as Samuel from Mystery of the Emblem and Shannam from Thracia 776.
- Upon defeating Dark Yashiro, a costume based on him can be purchased for the real Yashiro at Anzu Tokyo Store.