Daredevil

Regardless of your goals or ambitions, a key motivator for you has always been the rush of adrenaline that surges through your veins whenever you dodge swords by a hairs breadth, sneak past enemies so close you could almost touch them or unlock an ancient door and rush through it just before a rolling stone crushes you. Rogues that embrace this aspect of them not only thrive, but excel under pressure. They often see improvement of their skills as an end by itself, priding themselves on their achievements.  They are constantly on the lookout for a new challenge to best with their unparalleled reaction time, unpredictable motions and their ability to overcome obstacles with single focused bursts of power. Thus this kind of Rogue is naturally found exploring, seeking out the most difficult bounties or exploring dangerous ruins for the thrill of it, but can also be seen among the darker parts of society, stealing extraordinarily well protected items or taking assassination contracts on highly safeguarded nobles simply because they can.

Momentum

Starting at 3rd level you learn how to build up momentum during combat and use your actions to step by step control the fight. You gain access to a new resource called Momentum which can be spent to activate Momentum Actions.

You start each combat with 0 Momentum and lose all Momentum at the end of combat. At the end of your turn during combat you gain +1 Momentum. If you hit with at least one weapon attack during your turn, you gain +2 Momentum instead. If any of those attacks were sneak attacks, gain +3 Momentum instead.

Your Momentum maximum equals half your rogue level rounded up. Momentum Actions can only be used during combat and unless stated otherwise, only on your turn. There is no limit to the amount of Momentum Actions that can be invoked per turn.

As you level up your arsenal of Momentum Action expands with access to more straining, but also more powerful techniques. At level 3 you get to choose three Tier 1 Momentum actions. At level 7 you get to choose a Tier 2 and a Tier 1 Momentum Action. At level 15 you get to choose a Tier 3 and another Tier 2 Momentum Action.

Momentum save DC = 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice)

Tier 1 Momentum Actions

• Best under Pressure : You are at your best while your life is in danger. Spend 1 Momentum to gain advantage on your next skill check. This effect can be invoked outside of your turn.
• Precise Strikes : You see a drop in your enemy's guard and strike faster than they can react. Spend 1 Momentum to add 1d4 to your next attack roll this turn. An attack can not benefit from this feature more than once.
• Deadly Strikes : You strike a distracted enemy and in a split-second decision redirect it. When you roll damage for a sneak attack, you can spend 2 Momentum to re-roll your sneak attack damage dice. You must use the new roll.
• Bleeding Wounds : You unleash a carefully aimed strike to bleed your enemy out. Spend 2 Momentum to apply a bleeding wound to a creature with your next weapon attack this turn. When you hit the creature has to make a Constitution saving throw. If it fails, the creature is bleeding and takes 1d6 bleeding damage at the start of its turn, on a success the bleeding stops. The target can repeat the saving throw at the end of its turn. Magical Healing as well as a successful Medicine check against your Rogue DC also stop the bleeding.
• Sprint : The adrenaline running through your veins makes you feel as if time slowed down. Spend 1 or more Momentum to add 10 feet per Momentum spent to your movement this turn.

Tier 2 Momentum Actions

• Swift Strikes : In a surge of adrenaline you strike swiftly. If you have taken the attack action this turn, you can spend 3 Momentum to make another weapon attack. You can only use this Momentum Action once per Turn.
• Split Second Rescue : You react in the nick of time to save your friends. If any of your allies within range is affected by a spell requiring a Dexterity Saving Throw, you can use your reaction to spend 1 or more Momentum to move to that ally and grant them the benefit of your Evasion feature. The range of this feature equals 5ft per Momentum spent. If this movement brings you within the effect radius of the spell, you are also affected by it. You do not gain the benefit of your Evasion feature for this saving throw. You can use this Momentum Action outside of your turn, but overall only once per round.
• Uncanny Dodging : You prepare to perform miraculous dodges against an incoming onslaught. Spend 3 Momentum on your turn to get the ability to use Uncanny Dodge once without expending your reaction. This effect lasts until the end of your next turn. You can only use this Momentum Action once per Turn.

Tier 3 Momentum Actions

• Faster than the eye : You move so fast that the naked eye can no longer keep track of you, surpassing reflexes that even the fastest of creatures have developed. Spend 4 Momentum, for the next minute any creature has disadvantage on attack rolls against you. An attacker is not put at disadvantage if it doesn't rely on sight, as with blindsight, or can see through illusions, as with truesight. You also don’t need advantage on the attack roll to use your Sneak Attack against a creature while this ability is active. If you use this Momentum Action again before finishing a long rest, you gain a level of exhaustion.
• Heightened Senses : You close your eyes and strain all your senses to their limit, allowing you to perceive the finest details and react almost as if you had precognition. Spend 4 Momentum to gain blindsight in a range of 60 feet for the next minute. Each round you can take one additional reaction beyond the first. If you use this Momentum Action again before finishing a long rest, you gain a level of exhaustion.
• Enduring Body : You strain all aspects of your body to their limit. Spend 4 Momentum to become proficient in all saving throws for the next minute. If you use this Momentum Action again before finishing a long rest, you gain a level of exhaustion.

Bonus Proficiencies

You have overcome your fair share of daring vehicle chases in your time so far, or at the very least wanted to try it out once. Starting at 3rd level when you choose this archetype you gain proficiency with land vehicles.

Cunning Action - Mobile Fighting

Making use of your increased speed during combat expands your cunning action options. When you choose this archetype at 3rd level you can also use your cunning action to Grapple or Shove a creature.

Overstress

At 9th level you have learned how to push beyond what's normally possible for a short amount of time, thinking three steps ahead during conversations, straining your body and its senses to their limits, or reaching intense mental focus to process or remember information. You can use this feature as a bonus action to gain advantage on your next skill check. If you use this feature again before having finished a short or long rest you gain a level of Exhaustion. If you use this feature for a check whose action takes longer than 10 minutes, take a level of exhaustion for every 10 minutes over the initial 10 minutes.

Superior Reflexes

Starting at 13th level you have honed your reflexes to an unnatural degree. You gain the following benefits :

• You are too nimble to be struck during movement. Attacks of opportunity against you are at disadvantage
• Nobody reacts faster than you do. You gain advantage on initiative rolls.

Overwhelming Momentum

Starting at 17th level you have learned how to start combat and immediately push it in your favor. You start combat with 5 Momentum instead of 0 Momentum.