Unknown to Irisviel, Saber, or even Caster who retreated first, the entire process of this chance meeting between them was under the surveillance of pursuers.

In the dense forest connected to the state highway, the pursuers wearing the ghastly skull masks concealed themselves on the treetops swallowed by the darkness, and surveyed all that just happened with a vigilant eye.

Not just melting into the shadows; the pursuers who cut all of their scents to evade Saber's senses seemed to be shadows themselves. No one else can achieve this apart from Assassin. Looks like Assassin, according to Kotomine Kirei's command, followed Saber and Irisviel from the warehouses to here.

- Fate/Zero: Act 5, Part 1