The Way of the Howling Echo teaches that words have power, and to exercise the utmost care in when to speak and what to say, so as to not misuse the gift of language. Monks of this tradition are thus often called "Echoes," as they often only speak if spoken to. There is truth to their teachings, though; Echoes are taught certain words of power, and learn more as they go along, that demonstrate to all who witness them why such discretion is required when considering your next choice of words.

Echoes of Magic and Might

3rd-level Way of the Howling Echo feature

You gain proficiency in the Arcana and Intimidation skills.

Howls of the Echo

3rd-level Way of the Howling Echo feature

Your voice carries with it mystical powers. As an action, you can channel your ki into your vocal chords and spend 1 ki point to use one of the Howls below. All Howls' effective ranges are either a 45-foot cone or a 30-foot radius sphere (indicated in each Howl's description), originating from yourself in both cases. All Howls, unless otherwise stated, can be heard up to 120 feet from you when used, and some Howls have extra effects that can be triggered for an additional ki point. If a Howl has a lasting effect, that effect ends upon using a new Howl, even if the new Howl is an instantaneous effect. You can use your Flurry of Blows even if you use your action to Howl.

These Howls are available to you at 3rd level. You gain additional options at 6th and 11th level.

Howl of Soul Sight - (Sphere) Until the start of your next turn, you can see all living creatures within range, even through total cover or if blinded, or if the creature is invisible. This Howl is a whisper; it can only be heard up to 5 feet away when used, though its effective range is unchanged. You can spend an additional ki point to extend this duration to 1 minute, but the effect requires your concentration (as if you were concentrating on a spell).

Howl of the Rift Walker - (Sphere) Choose a number of creatures within range equal to or less than your proficiency bonus. Each chosen creature, as well as yourself, immediately has the Blink spell cast on them. The Howl moves with you, but when you are on the Ethereal Plane due to this effect, the Howl remains centered on the space you previously occupied until you return to the Material Plane. If a chosen creature leaves the range of the Howl or reappears outside the Howl, the spell ends on them. 

Howl of Faltering Grasp - (Cone) Creatures within the affected area must make a Strength saving throw against your ki save DC. On a failed save, they must drop anything they are carrying with their hands or similar limbs and take thunder damage equal to two rolls of your Martial Arts die + your Wisdom modifier. You can spend an additional ki point to impose disadvantage on this saving throw.

Howl of Wavering Courage - (Cone) Creatures within the affected area must make a Charisma saving throw against your ki save DC or be frightened of you for 1 minute. You can spend an additional ki point to impose disadvantage on this saving throw.

Howl of the Flightless - (Sphere) Creatures within range which possess a flying speed have their flying speed reduced to 0 and cannot hover for 1 minute. Any creature that enters this Howl's range within its duration is also affected until the duration expires. This Howl is a whisper; it can only be heard up to 5 feet away when used, though its effective range is unchanged. You can spend an additional ki point to exempt a number of creatures equal to your proficiency bonus from this effect.

Howl of Heavy Limbs - (Cone) Immediately cast the Slow spell on all creatures within range. When you cast this spell in this way, it uses your ki save DC and occupies your concentration.

Auditory Filter

6th-level Way of the Howling Echo feature

Your ears filter out unnecessary noise, and hone in on words of interest. You gain resistance to thunder damage, and your passive Perception increases by 5.

Adept Howls

6th-level Way of the Howling Echo feature

Your ki enriches your voice further, granting you more powerful ways to use your Howls. The following Howls become available to you, following the same rules as those you obtained at 3rd level:

Howl of the Elements - (Cone) All creatures within the area of this Howl must make a Dexterity saving throw against your ki save DC. On a failed save, they take damage equal to two rolls of your Martial Arts die plus your Wisdom modifier. The damage type is your choice of acid, cold, fire, lightning, or poison. You can spend an additional ki point to inflict an extra effect to all affected creatures based on the damage type you chose: Acid causes attack rolls against them to have advantage; Cold reduces their speed by half; Fire deals half the initial damage rolled at the start of the creature's next turn; Lightning stops affected creatures from using reactions until the start of their next turn; and Poison causes a creature to become poisoned for 1 minute. On a successful save, a creature takes half damage, and will not suffer any extra effects.

Howl of Clamoring Tempest - (Sphere) You cast the Storm Sphere spell, with some changes. The spell occupies your concentration as normal, but rather than creating a storm somewhere you can see, the cloud fills the sphere of your Howl, which moves with you. You take no damage from this effect, are not hindered by its difficult terrain, and do not have disadvantage on Perception checks. The spell attack described in the spell can be made immediately at the start of your turn as a free action, rather than taking a bonus action. If you do anything else on your turn before this spell attack, it uses a bonus action as normal. Wisdom is your spellcasting ability for the purposes of this spell.

Howl of Desired Demise - (Cone) Creatures within the area of this Howl must make a Charisma saving throw against your ki save DC. Until they save 3 times, a creature feels a force of death looming over them, imposing disadvantage on their attack rolls and saving throws, and granting advantage to attack rolls against them, for up to 1 minute. An affected creature makes another saving throw at the start of each of its turns. This Howl only affects those within its area at the time of its use, and does not linger for others who would enter its area.

Master Howls

11th-level Way of the Howling Echo feature

Your path as an Echo is reaching its apex as you learn the final Howls. The following Howls become available to you, following the same rules as those you obtained at 3rd and 6th level:

Howl of Spirit Feasting - (Sphere) All creatures within the area of this Howl must make a Constitution saving throw against your ki save DC. On a failed save, they take necrotic damage equal to two rolls of your Martial Arts die plus your Wisdom modifier. On a successful save, they take half damage. Regardless of how many creatures succeed or fail, you gain 5 temporary hit points for each affected creature. You can spend additional ki points to increase the temporary hit points you gain by 1 per affected creature for each ki point spent. You can exclude creatures from this effect by spending one ki point per creature spared.

Howl of Soul Chains - (Cone) Any number of creatures you choose within the area of this Howl must make a Charisma saving throw or become immediately bound by ethereal chains, causing them to be restrained. While restrained in this way, a creature is also restricted from extraplanar movement, including teleportation and planar travel, and their soul cannot leave their body even if the body is killed. These chains last until your concentration is broken, up to a maximum of 24 hours, even if you use another Howl in the meantime.

Howl of Astronomical Force - (Cone) All creatures within the area of this Howl must make a Strength saving throw against your ki save DC. On a failed save, they take force damage equal to four rolls of your Martial Arts die plus your monk level, and are thrown backwards a number of feet equal to twice your Wisdom score, rounded up to the nearest 5. On a successful save, they take half damage and are not moved.

Eternal Echo

17th-level Way of the Howling Echo feature

They will hear the echoes of your story for generations. You can use 2 Howls with the same action, using ki points for each as normal, as long as they occupy the same area. Whenever you use a Howl, roll a d20; on an 11 or higher, you do not expend a ki point for that use of that Howl. Extra effects always expend ki points.