actively losing hit points

[sreservoir]

I can't think of any complete (by which I mean "has enough solutions to problems to make a character viable on its own") subsystems which actively expend hit points as a limiting factor.

hp are a limiting factor for everyone, of course -- you can't act when you're dead -- but only reactively.

so I pose this question: what complete subsystems exist for 3.5e which use hit points as the principal unit of cost for its effects? (are there any?)

[HunterOfJello]

Hellfire Warlocks take ability damage to their Con score in order to use their hellfire blasts. Considering the fact that Warlock damage is pretty lousy without dipping into the class and using the hellfire, it is both a large necessity and a limiting factor for the class.

The general solution to the ability damage problem is to take a level in Binder.

[sreservoir]

hit points

ability damage

... er. hm

there are enough things that take ability damage as a cost that Naberius's FAH is almost negligible for the actual binder, but has possibly wider-reaching effects on the game than any other vestige. see also. (http://brilliantgameologists.com/boards/index.php?topic=4124.0)

[dextercorvia]

Not complete subsystems, per se, but Overchannel, Words of Creation (non-lethal), Blade of Blood spell, and Reserves of Strength (on a stun immune character).

Of those, Overchannel is probably the most widely available, and as a concept a Psionic character, constantly pushing himself past his physical limits could work.

[Psyren]

Bonus points if you fluff it using the standard method. (http://tvtropes.org/pmwiki/pmwiki.php/Main/PsychicNosebleed)

[Big Fau]

There's a Soulmeld that uses your own HP to heal other people (Lifebond Vestments, IIRC).

[Psyren]

Vitalists (and Egoists/Telepaths to a lesser extent) also heal others by absorbing their wounds onto themselves. Two (http://www.d20srd.org/srd/psionic/powers/sharePain.htm) powers (http://www.d20srd.org/srd/psionic/powers/empathicTransfer.htm) facilitate this technique.

[Anxe]

Blood Magus from Complete Arcane?

[EnnPeeCee]

I actually asked a similar question (http://www.giantitp.com/forums/showthread.php?t=200912) not too long ago. One thing that came up that caught my attention was the warforged feat Shocking Fist that lets you sacrifice health to do bonus damage on your slam attacks.

[Kaje]

Tainted Sorcerers can take hp damage to ignore inexpensive material components. Why they'd do so beyond very specific instances is beyond me.

[Zaq]

As EnnPeeCee mentioned, warforged can burn HP to do a few things (Shocking Fist is fun, and they can also burn HP to make bolts for their armbows, if they have 'em).

I thought there was something like this in Dragon Compendium, but I'm not seeing it on a quick flip through.

[faceroll]

There's a magic weapon that does damage to the wielder (but more to whoever you hit), and a Paladin spell that lets you sacrifice HP to do more damage or something.

[Firest Kathon]

There is a Chaos Mage class (I don't recall the source though). Whenever she casts a spell, she takes nonlethal damage - unless she fails a spellcraft check, then it's lethal damage.

[Steward]

Tainted Sorcerers can take hp damage to ignore inexpensive material components. Why they'd do so beyond very specific instances is beyond me.

Maybe they forgot to take the Eschew Materials feat? Or does this effect apply to even components that have a specific gp cost?