Tokubetsu Jōnin

are ninja who, rather than all-around jōnin training, have jōnin-level ability in a specific area or skill, much like warrant officers in real-world militaries. They are elite specialists in their areas and are often assigned as subordinates to regular jōnin when their services are needed.

Trivia

 * Tokubetsu jōnin are called elite shinobi.