Way of The Four Pillars

During the ordering of Aleria, The Shaper and The Flame worked together with the progenitor races to seal away the raging elements. To do this, they created the elemental planes as not only prisons but sanctuary and a plane to rule. Left behind were four nexuses of power tied to each of the Planes of Earth, Water, Fire, and Air. Left to safeguard these places of power, the Titans left behind those with the strength and wisdom to wield the elements, but also the discipline to not abuse this power. 

Elemental Styles

When you choose this tradition at 3rd level, you learn to harness the power of the elements in your martial arts through four unique stances.

Entering a Stance:  As a bonus action, you can spend 2 ki points to enter one of the elemental stances listed below for 1 minute. Using this feature while an elemental stance is already active ends the current one.

Air Stance:  Winds swirl about your body and powerful gusts fly from your fists. Your Step of the Wind ability doesn't cost ki, and when you hit a creature no more than one size larger than you with a monk weapon or unarmed strike, you can push that creature 5ft. in any direction.

Earth Stance:  You plant your feet firmly in the earth, armoring your body in enduring stone. You have advantage on ability checks and saving throws to avoid being forcefully moved or knocked prone. When you enter this stance and at the start of each of your turns, you can choose to half your movement speed and gain +2 AC until the start of your next turn.

Fire Stance:  You wreathe your body in biting flames. Once on each of your turns, when you damage a creature with a monk weapon or unarmed strike, you can deal additional fire damage equal to your martial arts die. You can also use your reaction to deal this fire damage to any creature that hits you with a melee weapon attack.

 Water Stance:  Whip-like tendrils of water spread from your body. Your unarmed strikes gain a reach of 15 feet. When you hit a creature that is no more than one size larger than you with an unarmed strike, you can force it to succeed on a strength saving throw or be held by your tendrils, reducing it's speed to zero for the duration of your water stance or until you move more than 15 feet away from it. A held creature can repeat this saving throw at the start of it's turn, ending the effect on a success. You can forgo your movement on your turn to move any creatures held in this way to an unoccupied space you can see within 15 feet of you.

Elemental Attunement

Starting at 6th level, your continued training allows you to exert minor control over the elemental forces at will. 

You learn the Control Flame, Gust, Mold Earth,  and Shape Water cantrips. Wisdom is your spellcasting modifier.

Deflect Elements

Also at 6th level, you can bend elemental forces to protect yourself and your allies.

When you make a saving throw against an effect that deals acid, cold, fire, lightning, or thunder damage, you can spend one ki and use your reaction to grant yourself and any allies you can see within 10 feet of you advantage on a roll.

Elemental Mastery

By 11th level, you've achieved mastery over the individual elemental styles. You gain the following mastery benefits depending on which stance you are in.

Air Mastery:   When you enter your Air Stance, you also gain a fly speed equal to your move speed for the duration.

Earth Mastery:  When you use your patient defense while in Earth Stance, you also gain temporary hit points equal to half your monk level plus your wisdom modifier.

Fire Mastery:  As an action while in Fire Stance, you can spend 2 ki to unleash a wave of fire in a thirty foot cone. Each creature in the cone must make a dexterity saving throw, taking 8d6 fire damage on a failed save or half as much on a successful one.

Water Mastery:  As a bonus action while in Water Stance, you can spend 2 ki to force each creature in your reach to make a strength saving throw. On a failed save, the creature suffers damage equal to your martial arts die plus your wisdom modifier and is held by your Water Stance tendrils, provided it is no more than one size larger than you. Creature that succeed take half this damage but suffer no other ill effect.

Harmony of the Four Pillars

At 17th level, you are able to keep opposing elemental forces in perfect balance, entering multiple stances simultaneously.

When you enter a stance, you may enter two stances instead of one, gaining the benefits of both. You can also spend up to additional 4 ki, entering an additional stance for every 2 ki spent in this way (6 total ki for all four stances).