User blog comment:Hitsuji Mamoru/Servant Creation Room 2 : Guess of the Who/@comment-31726296-20170716021510/@comment-31726296-20170716151658

Your correct FGOHikaru about this doujin is not a work that has been adapted into Anime or other mainstream media.

Also Hitsuji Mamoru you are correct about the anonymous speaker is a mascot-like mystic code/item. in addition also being correct on its name.

Well all you need to is find out is what ??? is replacing in the skills ??? and ??? Magecraft

here is another hint, Caster's NP is a variation of someone else's NP. Or if you to be really Pacific Caster's NP was someone else's Buster attack.

hope this helps. If not this might be another FAILURE for sure. : (