A Chapter Master is in charge of one Chapter of Space Marines. Chapter Master is the highest rank available to a Space Marine. He is assisted by the Cheif Librarian and Chaplain in most cases. As well as managing the Space Marines at his command, and the Company Captains under him, he also has a duty to his Chapter's homeworld, to govern it and protect it. He will be highly skilled in tactics, fighting and leadership.
Notable Chapter Masters
Azrael, Chapter Master of the Dark Angels
Commander Dante, Chapter Master of the Blood Angels
Marneus Calgar, Chapter Master of the Ultramarines
Logan Grimnar, Chapter Master of the Space Wolves
Temuchin, Chapter Master of the White Scars
High Marshall Hellbrecht, Chapter Master of the Black Templars
Pedro Kantor, Chapter Master of the Crimson Fists
Tu'Shan, Chapter Master of the Salamanders