He used Black Keys during ranged battle. A single throw, complete with preparatory movements, could be completed in 0.3 seconds. He could perform four separate throws in 0.7 seconds. His accuracy rate was 100% even when striking down unconfirmed targets, such as the illusions in the Einzbern forest. The blades themselves, half-spiritual entities, could penetrate iron.

He used Baji Quan for melee fighting. Specific details were unclear, but he was undoubtedly at the level of an expert. He had seriously injured Maiya, a dagger-wielding opponent, with just one strike, and snapped a fully grown tree in only a few strikes.

The frock he wore had been reinforced with bullet-proof materials, and processed to protect against spells. It would protect him, at the very least, from 9mm Parabellum bullets.

Pre-battle intelligence gathered from other fields:

According to the magecraft teaching result reports obtained from Tōsaka Tokiomi, Kotomine Kirei’s tutelage of magecraft had not progressed beyond the degree of a beginner. His most outstanding skill was spiritual healing. If he were to use any effective magecraft during battle, then the only predictable one would be physical enhancement; his most adept skill, used to exert even greater physical strength.

Lastly, predicting his battle tactics.

Since Emiya Kiritsugu had thoroughly hidden himself, the most information Kotomine Kirei could obtain to analyze Kiritsugu’s tactics would consist of rumors. The only battle in this Heaven’s Feel that had forced Kiritsugu to use his ‘secret weapon’ was the fight against Lord El-Melloi. The bounded field of the Einzbern Castle at that time had still been dense enough to prevent the Assassins from penetrating too deeply. Moreover, Kirei himself had been battling Maiya and Irisivel during that time. It was impossible for Kirei to have found out about Innate Time Control, or the ‘Origin Bullet’. It could safely be assumed that he would not have countermeasures for these.

– That was all the information that Emiya Kiritsugu had gathered concerning the final decisive battle.

- Fate/Zero: Act 16, Part 6