Immortal Vanguard

The Immortal Vanguard come from highly disciplined training to maintain excellence in harsher weather and conditions than the average soldiers can to thrive in the frontlines of combat. They rely on a lighter armor to better survive weather conditions and a versatile array of weapons to quickly use in a pinch with sharp reflexes that always cover gaps their enemies may have on the battlefield being better equipped.

For those who have heard of the Immortal Vanguard, they dismiss the rumors of them with statements that it is merely a battlefield illusion used by their strategists. They're said to have a large number of similar looking units that are ready to replace their fallen and startle their enemies on the battlefield from the tales of battlefield immortality. For those who have seen the vanguard in battle, they will recount far different memories most can confirm they have seen many of these soldiers appearing similar to each other within their unit, but the retelling always differs noting how these soldiers have fought unencumbered by being surrounded by countless foes and environmental distractions on the battlefield around them.  

Despite having such a fierce background, these soldiers specialized to always remain coolheaded and calm in any situation. They can easily appear as a humble traveler, engaging with other townsfolk and savoring the simple pleasures in life that they personally understand the brevity of, but when needed, switch to a disciplined and deadly opponent that remains several steps ahead of their foes.

Armored and Agile

At 3rd level, you are more acclimated to fighting with lighter armor and having more range of movement to move and react more quickly than your foes. When you wear light or medium armor you can use your dexterity modifier instead of you strength modifier to attack with weapons that have the properties of Light, Thrown, or Versatile. 

Additionally, you gain proficiency with Slight of Hand and double your proficiency bonus making Slight of Hand checks when wearing light or medium armor.

Frontline Skirmisher

At the 3rd level, part of your training is knowing how to move swiftly between enemies and stacking them over one another to a more advantageous location to strike. You don't provoke attacks of opportunity from other enemies when moving if you're still moving within the threatened range of another enemy. 

Quick Strike. When wearing light or medium armor, if you move 10ft, you can use a bonus action to make an attack with a Sleight of Hand check against a target's AC. On a hit, you do 1d6 of a chosen melee weapon's damage type and add an additional +1d6 for every 5 points the check exceeds the target's Armor Class.

Combat Reflexes

At level 7, you are skilled at finding and creating opportunities within combat that you are capable of taking advantage of. 

At the start of each combat, you engage the enemy already keen of their flaws in organization and approach, you gain additional Reactions equal to your Dexterity Modifier (minimum of 1) that can be spent at any time. 

Additionally, you have a knack for spotting created opportunities to take advantage of, when you score a critical hit, you regain an additional Reaction that can be used. The max number of additional reactions you can store that combat is equal to your Dexterity Modifier.

Lightning Initiative

At level 10, you learned the best advantage against an enemy is being faster than them. You are skilled in only allowing foes to react and never strategize against you, you add your proficiency bonus to your initiative. 

When you're wearing light or medium armor: For targets below you in the initiative order, you gain a +2 bonus to your Attacks and Armor class, and your Slight of Hand checks are made at advantage.

Additionally, you can use a bonus action to study your enemies and anticipate their actions to act ahead of them, move yourself up one place in the initiative order unless you're 1st in the initiative order.

Pressing Assault

At the 15th level, missing an opponent is never likely to gain them any sort of advantage. When you miss an attack against an opponent, you can use your reaction to press forward with aggressive strikes intentionally directed at their defenses to expose them.

Until the start of the target's turn, they lose 1d4 from their Armor Class. This can't be done more than once a round.

Thin the Lines

At the 18th level, you are the legend that sweeps across the battlefield and can swiftly bring the end from one enemy to the next until there are no more within your reach to bring down. 

When you reduce a target to 0 hit points, you gain half your movement speed to move directly to a new target to take an extra attack action against and add any remaining damage done to your attack roll. 

You can do this a number of times equal to your dexterity modifier, you recover all expended uses after a short or long rest.