The best Martial Arts come from Military Traditions. The worst martial arts, like Italian Renaissance Fencing and German Longsword technique are derived from civilian traditions. Systema is a Martial Art which has evolved from the Military Tradition of the peoples of the Russian Steppe.
Systema is a uniquely Russian Martial Art and is fundamentally different from traditional Asian and Western European Martial Arts. Rather than try to explain this difference you are better to learn about it yourself, and you will not find better teachers than Mikhail Ryabko and Vladmir Vasiliev.
Any serious Student of the Sword should become acquainted with Systema, and Systema Sword Technique as there is much to learn from it.