Flagellant

This archetype focuses on funneling your desires to further your physical prowess. Whether that be through conditioning, or just pure masochism, you have inherently become a tool to take damage. 

Resolve

Your hit point maximum increases by 3 and increases by 1 whenever you gain a level in this class. When you are reduced to 0 hit points you can use your reaction to make a Constitution saving throw (DC 5 + the damage taken). On a success you instead drop to one hit point. You cannot use this feature if you are reduced to 0 hit points by a critical hit.

After the saving throw succeeds, you can’t use this feature again until you finish a long rest. 

Offering of Flesh and Blood

As part of your attack action you can choose to make one of those attacks against yourself. That attack automatically hits, regardless of your Armor Class. If you do this, the next attack you make is at advantage and deals additional damage equal to half of the damage you dealt to yourself with the previous attack..

You can only use this feature once per turn. 

 

Brief Respite

If you are at no more than half of your max hit points, you can use a bonus action to give yourself temporary hit points equal to your level + your Constitution modifier.  
You must deal damage to yourself before you can use this feature again.

Repentance

As an action, you can expend a number of hit dice up to your proficiency bonus, and take damage equal to the total rolled. This damage cannot be reduced or avoided by any means.  For a minute, you gain a bonus to attack and damage rolls made with weapons. This bonus is equal to half of the number of hit dice spent. 

Once you use this feature, you must complete a short or long rest before you can use it again. 

Enduring Punishment

When you are unconscious, you can choose to fail 2 death saves, and be raised with a number of hit points equal to half your hit point maximum. This counts as using your action for the turn.

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