This subclass is very much inspired by the 4th edition Spiral Tactician paragon path for warlords. The following description is taken directly from the 4th edition Martial Power book.

The Feywild, home of the eladrin, is a wondrous reflection of the world. Within that plane, beauty thrives that defies the worldly mind, but so too does evil. Eladrin are as prone to wickedness as humans are, and in a bygone age, the drow were also natives of the Feywild.

In a time long before other great empires, eladrin faithful to Corellon fought bitter wars within the Feywild against the followers of Lolth and other evil fey. These wars culminated in what came to be known as the Last Battle of the Spiral Tower. During that clash, the Corellon loyalists finally turned the tide and a hero was born. Ossandrya was an eladrin squad commander when the Last Battle of the Spiral Tower began. Drow and demons had taken the mythic site during a protracted battle that saw the eladrin fighting on many fronts. Several fruitless assaults on the enemy-held tower cost Ossandrya’s superiors their lives. With reinforcements unavailable, the eladrin commander was forced to lead the remaining troops against the drow. She devised a multipronged attack that utilized the eladrin’s fey step, taking the biggest risks on herself and having no regard for the tower’s ultimate fate. In the end, Ossandrya’s efforts proved successful. Although the Spiral Tower was reduced to a blackened spindle bereft of magic, the eladrin drove the drow out for good.

In time, the Spiral Tower was rebuilt. Ossandrya, who survived other campaigns that drove the drow out of the Feywild, eventually passed from the mortal realm. She is counted among legendary warlords. Within the ruins of the Spiral Tower, her story is recorded. Eladrin warriors across the Feywild study her brilliant strategies and tactics, many of which
require fey powers. You have studied Ossandrya’s story and schemes, or you have intuited similar ploys thanks to your fey nature. It could be that some combination of these possibilities influenced your course in life. You have a strongly tactical mind, a sharp sense of space and timing, and the ability to adapt your powers to tactical needs. These aptitudes serve you well in your battles, leading you toward the acclaim Ossandrya has long possessed.

Commanding Strike

When you choose this archetype at 3rd level, you can create opportunities for you allies. When you take the Attack action, you can replace one of your takes to have a friendly creature, that can see or hear you, make a weapon attack or unarmed strike, using their reaction. If the attack hits, they gain a bonus to the damage roll equal to your intelligence modifier.

Tactician's Insight

Starting at 3rd level, you can use your tactical insights to inspire allies. As a bonus action on your turn, you can give a creature, that can see or hear you, advantage on their next attack roll. Additionally you can spend a use of this feature to heal the creature for a number hitpoints equal to your fighter level plus your intelligence modifier.

You can heal a creature with this feature a number of times equal to your proficiency bonus. You regain all expended uses when you finish a long rest.

Tactical Mind

Starting at 7th level, your studious battlefield observations have sharpened your mind. You gain proficiency in your choice of either history or investigation.

Your superior focus also causes you to gain proficiency in Intelligence saving throws.

Proficiency - History

Gain proficiency in history.

Proficiency - Investigation

Gain proficiency in investigation.

Fey Tactics

Starting at 10th level, when a creature you can see attacks a target other than you, you can use your reaction to teleport up to 30ft to an unoccupied space within 5ft of the target, and impose disadvantage on the attack. Until the start of your next turn attacks against the targeted creature have disadvantage while that creature is within 5ft of you.

Fey Command

Starting at 15th level, you combine your fey magic with your tactical commands. When you forgo an attack to allow a friendly creature to make an attack using their reaction, that creature can choose to teleport to an unoccupied space they can see within 30ft either before or after the attack is made, but not both.

Spiral of Fey Death

Starting at 18th level, you and your allies can become a chaotic whirlwind of death. You can use your bonus action to grant you and friendly creatures who can see or hear you, advantage on attack rolls until the end of your turn. Attacks made by you and the chosen creatures, gain a bonus to the damage roll equal to your intelligence modifier. After each attack you make during this turn, you can teleport to an unoccupied space you can see within 30ft. Additionally, when you take the Attack action you can forgo each attack to have a friendly creature who can see or hear you, make a weapon attack or unarmed strike using their reaction.

Once you use this feature, you can’t use it again until you finish a long rest.