Monks of the Way of the Nine Sections dedicate themselves to mastering one of the deadliest martial art weapon there is, the nine section whip. 

Way of the Nine Section

When you choose this tradition at 3rd level, your special martial arts training leads you to mastering the whip. You gain the following benefits.

You gain proficiency with whips, if you don’t already have it. These weapons are considered monk weapons and are specialized for you. Many of this tradition’s features work only with your whip weapon. Furthermore, whenever you would be able to make an unarmed strike, you may strike with the whip instead.

Your whips become a special two handed weapon that deal either slashing, piercing, or bludgeoning damage your choice and it's reach is extended by 5 feet (This can not be paired with Great weapon master feat)

Whip Techniques

You can manipulate your ki through your whips to control the battlefield and strike fear into your enemies. Whenever you hit a creature with one of your whip attacks granted by your Flurry of Blows, you can impose one of the following effects on that target (only one effect can be used per turn and you can not use another monk feature in addition to this):

-If the target is Large or smaller, it must succeed on a Dexterity saving throw. On a failed save, you knock the target prone.

-It must succeed on a Grapple Check or be grappled, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you pull the target up to 15 feet (can not be pulled away from you)

-Attempt to disarm the target, forcing it to drop one item of your choice that it’s holding. It must succeed on a Strength saving throw. On a failed save, it drops the object you choose. The object lands at its feet.

-You choose a friendly creature who can see or hear you. That creature can use its reaction to move up to half its speed without provoking opportunity attacks from the target of your attack.

Ki Empowered Whip

Your attacks with your whip weapon count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.

You can use your reaction to spend a ki point to provide one of the following benefits (you must be within attack range of your target):

-Parry - When another creature damages you with a melee attack,  reduce the damage by the number you roll on your martial arts die + your Dexterity modifier

-Intercept - When a creature you can see hits a target, other than you, within your attack range of you with an attack, you can use your reaction to reduce the damage the target takes by one roll of your Martial Arts die + your Dexterity modifier (to a minimum of 0 damage). You must be wielding a whip to use this reaction.

Warding Whirlwind

Beginning at 11th level, as a bonus action, you create a warding aura of whips that fends off attackers. When you invoke this feature, Target one creature within your weapon attack range and yourself, you are considered to be under the effects of the sanctuary spell. The saving throw for this spell equals 8+ your Wisdom modifier + your proficiency bonus. (This ends if either targets cast a spell that uses an attack roll or causes the target to make a saving throw). This spell can end early as normal. If, at the end of a battle, this effect was not ended prematurely, you may invoke it again (only once). You regain use of this feature after a long rest.

Elemental Warrior

You gain the following abilities and can activate them by using ki points (you can not use this along with other monk features):

Water Whip: You can spend up to 2 ki points as a bonus action to imbue a whip with water that ebbs and flow causing a creature to be unbalance. A creature that you hit must make a Dexterity saving throw. On a failed save, the creature takes an additional 3d10 cold damage, plus an extra 1d10 cold damage for each additional ki point you spend, and you can either knock it prone or grapple it and pull it up to 15 feet closer to you. On a successful save, the creature takes half as much damage, and you don't pull it, grapple, or knock it prone.

Flame Whip:  You can spend up to 2 ki points as a bonus action to imbue a whip with flames that glow bright and burns brighter causing a creature to be blinded. A creature that you hit must make a Dexterity saving throw. On a failed save, the creature takes an additional 2d10 fire damage, plus an extra 1d10 fire damage for each additional ki point you spend, and you can  blind and grapple it. If grappled by this effect, the creature takes 3d6 fire damage at the start of its turn and at the end of its turn if it remains grappled. On a successful save, the creature takes half as much damage, and it is not blinded or grappled.

Lightning Whip: You can spend up to 2 ki points as a bonus action to imbue a whip with lightning that sparks and crackles causing a creature to be shocked and awe. A creature that you hit must make a Dexterity saving throw. On a failed save, the creature takes an additional 1d10 lightning damage, plus an extra 1d10 lightning damage for each additional ki point you spend, and you can deafened and stun it. If the target fails by more then your proficiency bonus it is paralyzed instead of stunned. On a successful save, the creature takes half as much damage, and it is not deafened, stunned, or paralyzed.