Kali
The Filipino Martial Arts, commonly umbrellaed under the name Filipino Kali, derive from the Philippines and constitute several modes of combat; ranging from hand-to-hand to knife fighting, the most common of stick fighting to bow-staff. Kali has many forms and lineages, many of which David has trained.
Kali is best known as a stick fighting art, but once transferred to knives becomes even more deadly.
Essentially, Kali is the art of destruction.