With the many anime cross-overs with games in Japan, one should not be surprised to see this collaboration coming despite the difference in themes. Fate/stay night’s Saber and Archer will be made available to players soon, which I presume are supposedly cash shop costumes.
The 2 characters will come with their own skills as well, which are replicated directly from the novel/ anime, staying true to the series. A new Fate/stay night anime series is reportedly scheduled later this year.