Purple Dragon Knight (Figher archetype)

'Purple Dragon Knights are a remnant tradition that has carried on through the years since the end of the ancient Draconic "Black" Empire. Once noble, their order fell into much disuse due to the nefarious history of the Black Empire, but have managed to survive in pockets under the new Imperial banner. Still pledged to protect the Immortal Emperor at all costs, they value their honour and will take the fight against evil beyond the Eternal Empire's borders. Most are simply tasked by their order with wandering the imperial lands as knights errant, relying on their judgment, bravery, and fidelity to the code of chivalry to guide them in defeating evildoers.'

'A Purple Dragon Knight inspires greatness in others by committing brave deeds in battle. The mere presence of a knight in a hamlet is enough to cause some orcs and bandits to seek easier prey. A lone knight is a skilled warrior, but a knight leading a band of allies can transform even the most poorly equipped militia into a ferocious war band.'

'A knight prefers to lead through deeds, not words. As a knight spearheads an attack, the knight's actions can awaken reserves of courage and conviction in allies that they never suspected they had.'

Note: This original class is lacking in power. I modified it in a way that I see fit, and placed an emphasis on Charisma for some of the abilities, for unique flavouring and balancing.

Rallying Cry

When you choose this archetype at 3rd level, you learn how to inspire your allies to fight on past their injuries. When you use your Second Wind feature, you can choose a number of creatures within 60 feet of you that are allied with you, the number of creatures equaling your Charisma modifier (minimum 1). Each one regains hit points equal to your fighter level, provided that the creature can see or hear you. Additionally, until the start of your next turn, each creature who regains hit points from this feature has either advantage on all attack rolls or advantage on all saving throws (your choice).

Royal Envoy

A Purple Dragon Knight serves as an envoy of the Imperial banner. Knights of high standing are expected to conduct themselves with grave. At 7th level, you gain proficiency in the Persuasion skill. If you are already proficient in it, you gain proficiency in one of the following skills of your choice: Animal Handling, Insight, Intimidation, or Performance.

Your proficiency bonus is doubled for any ability check you make that uses Persuasion. You receive this benefit regardless of the skill proficiency you gain from this feature.

Inspiring Surge

Starting at 10th level, when you use your Action Surge feature, you can choose one creature within 60 feet of you that is allied with you. That creature can make one melee or ranged weapon attack with advantage (no action necessary), provided that it can see or hear you. Starting at 18th level, you can choose two allies within 60 feet of you, rather than one.

Bulwark

Beginning at 15th level, you can extend the benefit of your Indomitable feature to an ally. When an ally you can see within 60 feet of you fails a saving throw, you can expend a use of your Indomitable feature to allow them to reroll their saving throw, as long as they can see or hear you, and must use the new roll.

Hold the Line

At 18th level, your ability to inspire others can bolster your allies against even the mightiest of blows. When a creature that is friendly to you and is within 10 feet of you drops to 0 hit points, you can use your reaction to inspire them with bravery. The creature drops to 1 hit point instead, and until the start of your next turn, immediately gains a bonus to their AC equal to your Charisma modifier. You can use this feature a number of times equal to your Charisma modifier, regaining all expended charges after a long rest.