Cave Crawler

In the close quarters of cave tunnels or dungeon hallways, some rogues excel at sneaking where no one else could fit, and using the limited environment around them to their advantage. 

Back to the Wall

Starting at 3rd level, you know the value of keeping your back to a wall and using it as leverage against attacks. While adjacent to an object that is at least your height, you treat any effect against you as if you had ½ cover, even if you wouldn’t. If two or more different sides of you are adjacent to an object that is at least your height you treat any effect against you as if you had ¾ cover. In addition, attacks cannot have advantage against you while you have ½ or ¾ cover. 

Tight Squeeze

Starting at 3rd level, you are adept at fighting in small spaces. You can occupy a space of a size category one smaller than yours (to a maximum of small size) without having to squeeze. You can also move through an enemy’s space, treating it as difficult terrain.

Anticipate Defense

At 9th level you can better sense the shifts and movements of enemies within close proximity to you. You gain a blindsight of 10 feet, and if you attack an enemy in that range who is adjacent to an ally or an object that is at least their size then you gain advantage on the attack roll.

Dart Through

At 13th level you can sneak by enemies you wound to gain better positioning in close quarters. When you successfully deliver sneak attack damage to a creature, if you are within 5 feet of them you can move to any other point that is still within 5 feet of them. This doesn’t use any of your movement and doesn’t provoke attacks of opportunity.

Back to Back

At 17th level, you are proficient in taking advantage of defense provided by fighting in a team. If you are adjacent to an ally who is not within 5 feet of an enemy, any attack roll against you or that ally has disadvantage.