Synergies with being at low HP all the time? (or negative with temp HP)

[Covert Operator]

What I'm interested in is abilities that synergize with being at low HP all the time, or allow me to sacrifice HP for boons. For example, the first ability of the Martyred bloodline lets me sacrifice 1 HP as an immediate action to gain +1 on a save/skill check.

I'm making a PFS unchained rogue (escapologist). It's designed to be as wacky as possible. You can skip past this list if you want.

• Half Elf
  
• Racial Heritage: Kitsune
  
• Fox Shape feat lets me turn into a fox at will
  
• Weapon Prof: Elven Branched Spear is a reach finessable weapon that I can add Dex to DMG with.
  
• Minor/Major Magic Talent with Elven FCB gives many uses per day, and Kitsune Star Gems are 750 gp recharges (Pearl of Power for Spell-Like Abilities)
  
• Bookish Rogue feat lets me spend 10 min to change the spell associated the the Magic talents
  
• Takes levels in the Evangelist prestige class
  
• Has a Climb speed and a Swim speed
  

And finally, I have a plan for level 11. I become VERY hard to kill through damage.
I take these talents:

• Resiliency (1/day gain 2xlevel temp hp when I would be KO'd)
  
• Multitalented (use Resiliency 2 more times per day)
  
• Defensive Roll (make a reflex save to halve damage anytime I would be KO'd)
  
• In addition, the Escapologist ability lets me become Staggered to roll an Escape Artist check in place of a Reflex save or an attack vs my AC, after the original defence has failed.
  

[johnnythexxxiv]

Too bad you decided to grab Racial Heritage (Kitsune), I would have recommended Goblin instead. It lets you grab Roll With It, one of the strongest damage reducers in the game. Made a Dex based Barbarian that gained an effective DR 230/- by 20th because of it. Link if you're interested.

There aren't a ton of self damaging/does better while damaged abilities unfortunately. Kineticists have burn, Pain Tasters have Masochism and Bloatmages can go into a super rage that brings them to -1 once it ends, but other than that I can't think of anything. It makes sense that they're limited though, not a whole lot of people want to gimp themselves, even if it does put them ahead mechanically.

[Dekalinder]

Holy Vindicators have Stigmates, but are a totally different concept.

[Rynjin]

There is, of course, the Deathless line of Feats that chain off Die Hard, but that would require you to be a Half-Orc or have Racial Heritage: Orc instead. Those give you combat bonuses below 0 HP.

[lemeres]

A aether focused kineticist is pretty much the epitome of this.

Each point of burn gives you 1 nonlethal damage/level (so it is always taking a set percentage of your HP...except for the bit where your CON changes).

Aether's defense gives you 1 temp hp/level, and 1/2 your level in temp hp per point of burn you throw into that power. The temp hp heals per minute, and that regen increases with the burn mentioned above.

So you burn your hp by putting burn into that defense, but only half as much as other kineticists. And this is a great way to get the burn that activates elemental overflow and such.

Earth users are also rather good, since their defense lets them put burn into increasing their DR (which is already at invulnerable rager levels)