Sentries are highly-trained and elite guards who specialize in keeping secure areas safe from eavesdropping and invasion. They master polearms to help even them fend off enemies and learn to pick out suspicious details in normallyinadequate light. The most experienced among them develop a supernatural awareness of their surroundings.
Starting at 3rd level, you train with the specialized weapons used by guards and sentries in their duties. You gain proficiency with glaives, halberds, and pikes, and they count as adept weapons for you.
Also at 3rd level, when you are wielding a glaive, halberd, quarterstaff, pike, scythe, or spear, you may also make attacks with the haft. Treat the weapon as a double weapon and the haft end as a club when wielded this way.
Finally, at 3rd level, you have been trained to keep a very watchful eye out and summon reinforcements at the drop of a hat. You gain an expertise die on Perception checks and you can shout for aid as a reaction to seeing something that you deem suspicious or being attacked. In particular, this makes it very hard to silence you via spell or violence before you can shout for aid.
At 6th level, you have become inured to the long, mind-numbing hours of a sentry’s post or patrol and have learned to stay alert for extended spans of time. You can ignore the effects of one level of fatigue.
Your eyes have also become unusually good at picking out movement and detail that others might miss. You can take the Search action in combat as a bonus action.
Also at 6th level, you gain the Guarded Warrior feat.
Finally at 6th level, when you are wielding a quarterstaff, glaive, halberd, or pike, you can use the weapon to aid your jumps. You may spend 1 exertion to double your jumping distance (high or long), provided you have at least 10 feet of running start. If you have Gale Walk, this extends the multiplier from that feature to 5x normal distance when used as long as you are wielding one of the weapons listed above.
At 11th level, you never let your guard down entirely; not even when you are asleep. Being asleep does not impede your Perception checks based on senses other than sight or your passive Perception score, and you may choose to wake up in response to any detected stimulus. You can also stand up as a reaction, and if there is an unattended weapon you are proficient with in your space or an adjacent space, you may wield that weapon as part of the same reaction.
Also at 11th level, while wielding a glaive, halberd, or pike, you can ready and throw a thrown weapon or item (such as a vial of alchemist’s fire or a tanglefoot bag) as part of the attack action on your turn. This throw is in addition to your normal attacks with the attack action.
At 17th level, your ability to detect threats and danger reaches its apex. You gain blindsight and tremorsense, each with a range of 30 feet. If you already have one or both of these traits from another source, its range increases by 30 feet.