Agony Domain for 5e Clerics

My first 5e campaign is winding down, and folks seem to be enjoying it enough that we'll probably do that again. That being the case, I'm poking at some ideas for a post-apocalypse, dark-age sort of campaign. With that in mind, I'm crafting new character options to reinforce the themes. First of these is this Agony Domain. It's not been playtested yet, so if anyone does use it, please let me know how it works out.

The idea here was to create what amounts to a flagellant sort of mendicant cleric, the sort who'd wander about, stripped to the waist, thrashing themselves with knotted scourges and the like.  They acquire power from pain, so I tried to give them ways to fine-tune the damage they took, and then to profit from it.  Starting at sixth level, I can totally see PCs torturing themselves for the benefits of this class.

Agony Domain
There is a purity in pain, a mind-focusing wisdom that clears away all that is not vital and true. You might be an ecstatic masochist, seeking higher wisdom through pain, or a flagellant who wishes to purify mortals of the supreme sin of failing the gods in their greatest hour of need. Pain is your sacrament and your benediction.

Passion Domain Spells
Cleric Level Spells
1st Command, Heroism
3rd Beacon of Hope, Fear
5th Dominate Person, Geas
7th Mirage Arcane, Symbol
9th Shape Change, Weird

Experience with Pain

You have proficiency with marshal weapons.

Embrace the Agony

So long as your character is naked from the waist up and employs no magical AC enhancement, they enjoy resistance to all non-magical forms of damage, whether that’s blunt weapons, fire, acid, or whatever.

Channel Divinity: Share the Pain

Starting at 2nd level, you can use your Channel Divinity to inflict agonies you’ve experienced on one creature within 60’ of you. Your target needs to make a Constitution saving throw. Failure means they take as much damage as you have; that is, for every hit point you are currently below your max, they take one point of damage. If the target passes their saving throw, they take half that damage.

Serrated Illumination

Starting at 6th Level, the first time you are reduced to below half your hit point maximum in a fight, you regain all your level 1 spell slots.

Channel Divinity: You Can Take It

At 8th level, you can use your Channel Divinity as a reaction action to remove one status effect or active spell from another and put it on yourself.

The Ecstasy of Agony

At 17th level, every time you deal 2 or more points of damage to anything that can feel pain (not a construct or mindless undead) you may regain half as many hit points in healing, up to your hit point maximum.

Art by Carl Von Marr.