The Jedi Sentinels were a subsect of the Jedi Order that sought a balance between the two extremes of the Jedi, the Jedi Consulars and the Jedi Guardians. They possessed adequate combat skills and had somewhat extensive knowledge of the Force. Along with this blended knowledge of both combat and the Force, they also possessed exceptional non-Force skills, such as in the fields of security, computers, stealth techniques, demolitions, repair or medicine.
Sentinels also practiced a form of Force Immunity that crossed Force-based training with increased mental conditioning, allowing them to better withstand outside mental influences, including Force-based attacks. This allowed them protection from such powers as fear, stun and paralytic effects. Jedi Knights who followed this path were often dispatched to regions across the Galaxy in order to root out the dark side and to investigate unusual concentrations of the Force, similar to the Jedi Shadow and Jedi investigator. Traditionally, they wielded yellow bladed lightsabers, though this was not dictated as a rule of the Order. By the time of the Great Jedi Purge the title of 'Sentinel' appeared to have fallen into disuse.
The most notable Jedi Sentinel was Bastila Shan who, while still a Padawan, mastered the ancient and difficult art of battle meditation, using it to great effect to aid the Galactic Republic during the Jedi Civil War. Other Sentinels helped to rebuild the Order after the First Jedi Purge, all of whom were apprenticed to the Jedi Exile at some point during her adventures in 3,951 BBY.