@kwendy
I'm out of the loop for all the Fate spin-offs and I instantly have lots of questions.
Why is the guy able to use magecraft without family crest of training? Does he have mystic eyes?
Why are there seven servants in this era?
What with Einzbern wish?
What with Great Grail?
Why is not-Rin using makeshift portable summoning circle?
In order:
>Why is the guy able to use magecraft without family crest of training? Does he have mystic eyes?
You don't need a family crest to use magecraft, that's how all new mages start, even the ones from established lineages. You inherit your family's crest IF you're the heir and IF you're compatible with it. See also the OG, Shirou Emiya who similarly had next to no training and obviously no family crest but was able to use simple Reinforcement and Gradation Air magecraft.
>Why are there seven servants in this era?
Seven Servants is the "standard" for Holy Grail Wars, since the ritual is based on Alaya's (?)summoning of the Seven Grand Servants whenever a Beast appears.
>What with Einzbern wish?
Since this isn't Fuyuki City, the Einzberns are probably not involved in this. This is obviously an alternate timeline from mainstream F/SN, anyway, so don't expect to see the usual names, or at least not in their usual role.
What with Great Grail?
There might not be a Greater Grail here. Any magical source powerful enough to summon Servants from the Throne of Heroes can be designated as a Grail.
>Why is not-Rin using makeshift portable summoning circle?
Why not?