>>528089707
Imo it could be anyone from

>Herc cause he's Herc, but he has appeared in the bs advance quest already and I don't think they want to feature anyone from stay night

>Cu Alter for his riastrad form and so he can get an animation update. The only problem is that he is an alter and his FGO origins is kinda wonky. Also he appeared in an advanced quest already

>Raiko honestly just so she can get an animation update. But I think getting two nip grand candidates would make people mad so I doubt it

>Morgan cause she's Morgan, but I think it's more likely that Morgan Lily is the grand caster candidate

>Tez is likely, but I don't like the idea of complete divine spirit origins being a grand. Also the disjunct of an assassin being grand zerker would be weird regardless

If it were up to me, it would be Beochad himself. Like Musashi, he has reached what I would consider the pinnacle of the class through entirely mortal means. He literally bare fisted a giant and a dragon and no diffed them. Others like Herc still had to use strategy. Beochad just went unga bunga and won. There is no competition.