The circumstances that create fugitives are many and varied, but they all share a common thread: pursuit by a predatory force. Hunted as they are, fugitives live their lives keeping their heads down and getting away. Even ones who've escaped the hunt (for now) are incredibly hard to find if they don’t want to be.
At level 3, the harsh realities of life on the run require resourcefulness and the treatment of your own injuries. You gain proficiency with the Medicine and Survival skills. You can also carry 3 more units of Supply than normal.
You are also able to find what you need via dubious means. When you are in a village or near a farm, you can find enough food to subsist indefinitely with no checks required at no cost. The food is often unappetizing or at least bland, but it is safe to eat.
You are proficient with improvised weapons, and gain an expertise die on Sleight of Hand checks made to hide items on your person.
Also at level 3, once you have spent 24 hours in a new city, you can choose to acquire a city bolthole for free. You may only have one of these boltholes in any given city, but if one is discovered by your enemies, you can replace it after another 24 hours. You may have a maximum number of boltholes acquired by this feature equal to your proficiency bonus (each in a different community). If desired, you can decommission a bolthole over the course of 1 hour (clearing out possessions and removing clues) to set one up in a new location.
At 9th level, you have perfected the art of escaping from pursuers quickly. When you are not directly observed, you can make a disguise kit check as a bonus action. You also gain an instinctive knowledge of how cities work, and can ignore non-magical difficult terrain in urban environments.
Also at 9th level, you can use others around you to hide with special effectiveness. You have advantage on Deception and Stealth checks to remain unnoticed in crowds, and you can use a disguise kit or take the Hide action while in a crowd even while observed, forcing those that had eyes on you to make a new check to locate you again.
At 13th level, you can flee to a new location without leaving a trail. To do so, you must spend 24 hours preparing (cleaning out your residence, covering up your paper trail, planting false clues, and so on) and then promptly depart the location. Your trail goes completely cold, confounding even those concretely aware of your previous location with the multiple conflicting sets of evidence you left behind. Fleeing in this way grants you an expertise die and advantage on Deception checks to conceal your destination, point of departure, and personal identity for three days after your departure. Once you have used this feature, you must wait a week before you can use it again.
Also at 13th level, your fast-twitch reflexes and adaptive anxiety make it very hard to catch you off-guard. You have advantage on initiative checks and gain an expertise die on all Perception checks. You are also a very light sleeper, and you take no penalty to your Passive Perception due to sleeping.
At level 17, you have mastered the art of leaving your past behind. You gain proficiency with the forgery kit, and with a week to prepare and a DC 17 forgery kit check, you can create an entirely new identity for yourself that will stand up to all but the most intense scrutiny. Those attempting to penetrate your deception have disadvantage on their checks.
While inhabiting your new identity, even those who know you by sight must make a Wisdom saving throw against a DC of 8 + your proficiency bonus + your Intelligence or Charisma modifier (your choice) to recognize you. Even then, you have advantage on Deception checks to convince them they are mistaken.