The marshal is the highest ranking piece. However, they can be beaten by bomb. (And the spy to if the spy attacks the marshal.)
Chief of Staff
The Chief of Staff
The highest ninja rank is kage
The highest rank for a skill is 1
The highest rank is Tai Pan
The black belt is the highest rank in martial arts.
Domain is the highest rank in taxonomic classification.
The highest rank in Halo: Reach is Inheritor.
The highest rank you can reach is 46.
The highest rank in the Marines, by title and rank, is the Commandant of the Marine Corps. The position is currently held by 4-Star General James T. Conway. The position holds 4-Star General rank, regardless of the officer's actual rank. For example, a 2 or 3 star General can be selected and confirmed by the Senate for that position, and thereby gains 4-Star rank by virtue of holding that position, but would revert to their former rank when they left. That's why most retire after serving (your pension is based on highest rank achieved), though not all do.
Baiji - Baiji is the highest rank you can reach in sumdog, it's the 31st rank in sumdog.
The highest rank currently known in Platform Racing 2 is UnknownAx with a rank of 60, and he is tied with quesin, but UnknownAx hacked.