"What I learned from Kiritsugu, isn't limited to operating a car!"

As Maiya watched speechlessly and Kirei observed in surprise, Irisviel poured mana into the metallic threads. The thin threads became unraveled and moved between Irisviel hands like a living organism.

Kirei’s understanding was half correct. The Einzbern family possessed magic that was designed to forge, create, and more importantly, use matter. Kiritsugu could not have taught her any offensive magic. Originally, if one went solely by magical ability, Irisviel was far superior to her husband. Thus, Kiritsugu could not have taught her magic.

What he taught her was not how the homunculus lived. Rather, it was to use tears, laughter, joy and anger to sing about life – the meaning of the term “to live.”

In addition, he also taught her the determining to “live on.”

Kirei’s understanding was also half-wrong. Irisviel already had a method of turning her magic into offensive purposes as a “battle” state. It was something she learned from her husband, who always lived for battle – if she was to “live on” with him, she must face the test of “survival” one day. Thus, she will also need to face battle.

- Fate/Zero: Act 7, Part 1