Battle Assassin

In the heat of battle, a soldier turns to his commander for guidance and leadership. The Battle Assassin is a master at disrupting that chain of command by focusing on a single target and removing them amidst the chaos of battle, leaving their forces unprepared. They are trained to tap into a deep seated anger that runs through their veins and make it into a tool in times of war. 

Unlike their more stealthy counterparts, the Battle Assassin doesn't need to sneak into a castle to remove an upper target. They take them out as soon as they're seen on the battlefield, disregarding the lesser forces of soldiers and infantrymen in favor of their leaders. Avoiding strikes and turning the confusion of war into a useful tool on their belt, the Battle Assassin is a mobile killing machine one should hope to never anger.

Bonus Proficiecy

When you choose this archetype at 3rd level, you train to use weapons of every variety and use them in surprising ways. You gain proficiency in both Martial Weapons and Acrobatics. In addition, even if a weapon normally uses your Strength modifier, you can choose to instead use your Dexterity modifier so long it doesn't have the Heavy property and you are not wielding it with both hands.

Focused Rage

Starting at 3rd level, you have learned how to tap into your hatred and anger in... productive(?) ways. As a bonus action you can enter a Rage for up to 1 minute. You must either see the enemy or know they exist. You do not necessarily know that the enemy is present if you have not laid eyes on them. 

• All of your attacks deal sneak attack damage to the target you selected when you entered your Rage. However, you cannot deal sneak attack damage to any other targets for the duration of the rage. In addition, if you become aware that the target of your Rage has been killed by another's hand, your Rage ends prematurely. 
• You gain a bonus to damage rolls against non-targeted enemies equal to how many sneak attack dice you roll.
• Once your target dies by your hand, your Rage begins to simmer and quell. Your Rage will automatically end at the end of your next turn, giving you only a few moments escape potentially hostile territory.
• When Raging you have resistance to non-magical piercing, slashing, and bludgeoning damage. 
• If you wish to end this effect early while you believe your target to be alive, you must succeed on a Wisdom Saving Throw (DC = 10+your WIS modifier).

You can use this feature two times between long rests. This number increases to three at 6th level, four at 10th, five at 13th, and six at 17th.

Improved Uncanny Dodge

At 9th level, enemies not targeted by your Rage become even more trivial to you. In your single-minded fury, you don't even notice their attacks, your body merely avoids them as you charge through the ranks of fodder to take out their enemy. If you are targeted by an attack of opportunity while Raging, you can use your reaction to Disengage, causing the attack of opportunity to automatically miss provided you have enough movement to leave it's range. Additionally, all subsequent attacks of opportunity made against you this turn are made at disadvantage.

You may use this feature a number of times equal to your proficiency bonus between long rests.

Battlefield Maneuvers

You gain expertise in Acrobatics. If you already have expertise in Acrobatics, you gain expertise in a different skill in which you are proficient. In addition, when Raging your speed now increases by 5 ft. for each of your Sneak Attack dice and you can Hide from the target of your Rage amongst the chaos when there are at least 6 other Medium or larger creatures within 50 feet of them and there is a creature between you and them.

However, while Raging you can no longer use your Cunning Action feature to Dash.

Precision Rage

Starting at 13th level, you gain advanced insight into just how the target of your Rage fights. When you make an attack roll and the die comes up 19 while Raging, you score a critical hit. Also, when you score a critical strike against the target of your Rage, you triple the number of sneak attack dice you roll instead of doubling them.

In addition, if you would benefit from the normal Sneak Attack rules when attacking the target of your rage, you can roll one additional Sneak Attack die for damage. This benefit increases to two additional at level 18. These additional dice do not count for abilities that refer to your number of sneak attack dice. 

Barbarous Rogue

Beginning at 17th level, your mastery of your own rage has increased exponentially. As a Reaction, you can choose a new target that you can see for your Rage, even if you weren't the one to kill the previous target. You can choose to let your Rage die, however. In addition, when you make an attack against an enemy other than the target of your rage, you can choose to make a Wisdom Saving Throw (DC=16). On a success, the target of your attack becomes the new target of your rage. This includes the triggering attack. Once a target is changed in this way, you cannot change targets again until this one dies. Once they die, your target reverts to whoever it was before you changed targets. If your original target is dead, your rage automatically ends.