Way of the Abyss

Monks of the Way of the Abyss are obsessed with the chaotic power of the Abyss. They dedicate their lives to channeling its power through them. Their ultimate goal is to transform their soul into a timeless being beyond humanity. They excel in dismaying their opponents from defending themselves. Many have chosen this path because of their wish for immortality, ultimate freedom or fealty to some greater power. There are no monasteries for the way of the abyss, and any temple that had been established in the past was soon dissolved, mostly because of infighting or authorities. There have also been rare cases of monks finally attaining demonic immortality, before leaving the material plane behind, with chaos left in their wake.

The language of Chaos

At 3rd level you learn Abyssal, if you already know it, you instead learn Primordial.

Peer into the Abyss

When you choose this Tradition at 3rd level, you can manipulate your enemy's Ki to experience a piece of the eternal evil lurking within the abyss. Whenever you hit a creature with one of the attacks granted by your Flurry of Blows, your target must succeed on a Wisdom saving throw against your Ki save DC, or be frightened of you until the end of your next turn.

Crushing Rampage

At 6th level, you know where creatures should be after you leave them in your wake. Weak creatures can not stay on their feet, while facing your frantic charges.

Your unarmored movement increases by another 5ft.

Also at 6th level, whenever you move at least 15ft straight toward a creature and then hit it with an unarmed strike on the same turn, that target must succeed on a Strength saving throw against your Ki save DC, or be knocked prone and be unable to use reactions until the start of its next turn.

Debilitating Terror

At 11th level your ability to imbue fear into other creatures becomes even greater, making them powerless before you. If you successfully apply both Stunning Strike and Peer into the Abyss on a target in a single turn, the target also gets paralyzed until the end of its next turn.

Demonic Immortality

 At 17th level, Death on planes other than the Abyss becomes a minor nuisance to you. Whenever you die on another plane, your body dissolves into foul ichor. Then your body instantly reforms on one of the layers of the Abyss. 

In addition you can spend 15 Ki points to cast the Plane Shift spell to and from the abyss, without requiring material components.

After Dying from old age, you get reborn as a high ranking demon that retains control of its former Ki affecting abilities.