Second-floor clinic basement!
After mass-producing more than ten young clones, Duke extracted the souls from the crystal ball and bestowed new life upon them one by one.
Caster's magecraft attainments were truly poor. Though he had spent several years as a dark magician while alive and had researched souls, the crystal ball he used to store them was extremely crude. As a result, the souls inside were more or less incomplete, most obviously causing gaps in their memories after resurrection.
Still, being able to live once more was already a blessing. They could not ask for too much. Losing some memories was infinitely better than dying!
The blood Duke used for the clones came from Irisviel, so he had mass-produced a bunch of little silver-haired, red-eyed girls who looked exactly like her. What would Kiritsugu Emiya think when he saw these little brats...
Duke could step forward and testify that Irisviel had never done anything to betray him. Really!
As for the parents of those boys, Duke had nothing to say but sorry. Not only had their children lost their blood relation, they had even lost their little brothers.
Duke did not care whether these little brats could be recognized by their own families. If a child merely changed faces and their parents no longer recognized them, then... child, go find yourself a new family. They did not love you at all.
While Duke was churning out little silver-haired, red-eyed girls wholesale, Irisviel frantically dressed them in hospital gowns. Though the gowns did not fit, they were still better than being naked. Watching more than a dozen child versions of herself run around the room bare-assed while striking Ultraman poses and pretending to fire beams, Irisviel was nearly losing her mind.
Facing Irisviel's almost murderous gaze, Duke raised a thumb