User blog comment:Crimson and Darkness/Volume 25 discussion blog/@comment-3965848-20180510143442/@comment-120.188.37.204-20180510175815

Well, Ishibumi has a habit introducing a character and make him or her relevant in latter volumes. Dulio was first introduced back in volume 12 and later appeared in vol 15 or 16.

I would say that spectre dragon will becine relevant either in Shin or the next sequel