Game concept · All Under Heaven
Grand Marshal
The game also links it as Grand Marshal's.
From the game's encyclopedia
The Grand Marshal is the highest ranking commander in the Realm and commands an Army of Title Men-at-Arms.
The Marshal can be the designated Secretary Director, depending on the Grand Secretariat Control Law.
The minister can, for example:
• Start the Grand Campaign Great Project
• Start the Construct Great Barracks Great Project
• Use Seize Hegemonic County and Seize Hegemonic Duchy Casus Bellis in Expansion and Conquest Eras
• Access special Influence Career Interaction options
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Grand Marshal is an entry of Crusader Kings III's in-game encyclopedia (All Under Heaven). The game explains it: "The Grand Marshal is the highest ranking commander in the Realm and commands an Army of Title Men-at-Arms." It is part of Minister. The game also links it as Grand Marshal's. Patch 1.20.1.2, from game/common/game_concepts/tgp_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/tgp_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.