Grand Admiral a naval rank in one of the highest in the several European navies that use this system, what system are they using?
Military rank Military ranks are a system of hierarchical relationships in armed forces, police, intelligence agencies or other institutions organized along military lines. Usually, uniforms denote the bearer's rank by particular insignia affixed to the uniforms. Ranking systems have been known for most of military history to be advantageous for military operations, in particular with regards to logistics, command, and coordination; as time went on and military operations became larger and more complex, military ranks increased and ranking systems themselves became more complex.
Marshal (Italy) The Italian military rank of maresciallo (marshal) is classified as a "sub-officer" and is the highest rank of non-commissioned officer in the Italian armed forces, higher than the rank of sergeant but lower than that of ensign/second lieutenant; there are from three to five grades within the rank, according to the different branches of the armed forces. The rank is achieved through merit or attending the "Scuola Allievi Marescialli" (School of Student Marshals). Marshal is an intermediate rank of the armed forces which is currently granted to NCOs with the training and technical competence to carry out specialised executive roles, and to command smaller and technically complex units.