Prince of Persia
12 Achievements
200
17-23h
Xbox 360
Xbox One
Xbox Series
THE GATE KEEPER
You killed the chief guard.
15
How to unlock the THE GATE KEEPER achievement in Prince of Persia - Definitive Guide
You will find the chief guard in the 6th level. The 6th level is fairly short and this is pretty much the only enemy you encounter.
This achievement will be unlocked by playing through the story.