Feat Maker: Blood Magic

[Captain Kablam]

Hey thinking of introducing a new element into a campaign of mine with a feat that has both gameplay and thematic elements to it. I tried looking for an official WoTC equivalent, beyond the Blood Magus class, came up with nothing so I decided to home brew the below.

Blood Magic (Metamagic)
Some practitioners of the arcane have learned how to sap their very life's essence for greater, mystical power.

Prequisite
One must witness Blood Magic in use or have it be taught to them. Must participate in a ritual that allows them to use Blood Magic

Effect
For a permanent drain on the caster's vitality one can cast spells when they otherwise would be unable to. This includes not having the spell prepared or having used up all spells one could cast that day, and can even cast spells not on their spell list or barred by school or class restrictions, provided that one has the sufficient HD to cast such spells. The price paid is twice the effective level of the spell being cast (ie: Level 1 costs 2hp, Level 2 4hp, etc), and factors in the adjustment from metamagic feats. This health can not be substituted with temp hit points, and cannot be recovered through rest, healing, or regenerative spells and can only be claimed through the use of a Limited Wish, Miracle or other, similar sufficiently powerful spells.

Additionally, if one uses Blood Magic one a spell they do know, the effect is empowered at no additional cost.

Like I said, I'm using this for more plot purposes (the one they encounter using it is a cleric working herself to death treating the wounded in a refugee camp), and clearly has some game breaking potential, (barbarian casting fireball for example), but then again the fact that the health used is permanently lost does impose a rather dire restriction on players going forward.

So here are my concerns, is it too powerful? In what ways could it be abused by the players? And is there already an existing rule, feat, spell, etc. that would get the effect I'm looking for without endangering the game as a whole?

[noob]

The thing is you should probably cap the spells accessed in function of ecl with a rule like "the highest spell level you can use is your ecl+1/2" else you might just have some level 1 barbarian blood magic user use mind jar and then spam ninth level spells from the bodies of other people and recast magic jar from the body of someone else each time he goes near running out of duration(so every 3 hours because they can cast that spell that boost their cl of 2 for the next spell).
Because you know technically with one hitdice you can cast ninth level spells if you are an elven generalist domain wizard.
While it would be a cool bbeg it is not exactly a level 1 bbeg from the standpoint of his powers.
ps: can we transfer that thread to homebrew?

[Captain Kablam]

The thing is you should probably cap the spells accessed in function of ecl else you might just have some level 1 barbarian blood magic user use mind jar and then spam ninth level spells from the bodies of other people .

Thought about that, hence the "provided that one has the sufficient HD to cast such spells" line, though I should probably edit that to more clearly demonstrate that a level 4 barbarian can't just nix 18hp to cast wish. Clever trick, but it only works if during the time that same barbarian also puts their host body through the same ritual to get them to cast spells in such a way.

[noob]

Thought about that, hence the "provided that one has the sufficient HD to cast such spells" line, though I should probably edit that to more clearly demonstrate that a level 4 barbarian can't just nix 18hp to cast wish. Clever trick, but it only works if during the time that same barbarian also puts their host body through the same ritual to get them to cast spells in such a way.

Seems interesting.
So the requirement is "your body must have done the blood magic gain ritual"
I guess that makes ruling the world through draining the life-forces of others way harder.
Making the stuff based on hd is prone to having horrible effects with monsters.(like the classical monster that just take humanoid hit dice and so have a cr of his hit dice/4 now that monster would have spells of a level equal to twice his cr)
Maybe have it based on levels in classes since you intend on using it with classed npcs.

[Captain Kablam]

Well the biggest flaw I can think of is that if allowed this feat could destroy epic level play. Things going bad? Use a wish spell, you're a level 20 fighter after all you can afford it. Or not even need to be bother since you can just use a wish spell to heal back all your damage.

[noob]

Well the biggest flaw I can think of is that if allowed this feat could destroy epic level play. Things going bad? Use a wish spell, you're a level 20 fighter after all you can afford it. Or not even need to be bother since you can just use a wish spell to heal back all your damage.

You did say that only lesser wish, wish and miracle could remove the hp loss.
That does not means that wish remove the hp loss with ease maybe it costs 500 px per hp you regain meaning that the fighter could not spam his spells endlessly.
Also a wizard could already use wish.
This feat is not going to break epic play compared to what the spells already do.

[Anymage]

I repeat the claim that epic use is broken, since Miracle only costs XP for the most dramatic effects and one can just blood magic out a miracle. Then again, as broken as 17+ already are, I don't know that being more broken will be too substantially different.

At lower levels, though, it suffers for the intrinsic disparity that NPCs care less about long term debilities because noncombatants care less about combat stats while combatants will most likely be dead at the end of the scene no matter how they marshall their resources. CON damage to recharge a spent spell slot sounds more conceivably doable. Pulling any effect you want out of thin air is incredibly powerful. "Balancing" it with an obnoxious drawback doesn't change the impact when it's used one bit.

[Captain Kablam]

Pulling any effect you want out of thin air is incredibly powerful. "Balancing" it with an obnoxious drawback doesn't change the impact when it's used one bit.

I dunno, permanent hp loss does seem like a fair trade off given that yeah like you said, it gives you access to any conceivable spell, and you don't even have to be a spellcaster to for it to be used. Plus it's not entirely without merrit. Say you're squaring off against like say a frost giant and loosing badly, or an ally is bleeding out with nary a cleric or bard in sight. Recovering several d8s to just get you past the bad spot you're in seems like a fair trade for -6hp for the rest of your career.

[Fouredged Sword]

I dunno, permanent hp loss does seem like a fair trade off given that yeah like you said, it gives you access to any conceivable spell, and you don't even have to be a spellcaster to for it to be used. Plus it's not entirely without merrit. Say you're squaring off against like say a frost giant and loosing badly, or an ally is bleeding out with nary a cleric or bard in sight. Recovering several d8s to just get you past the bad spot you're in seems like a fair trade for -6hp for the rest of your career.

Characters will ether ignore this feature or slowly cripple themselves until the player retires that hero and rerolls.

This rewards treating your character as disposable.

I would suggest anyone being allowed to "heal" 1hp of loss a day at a cost of "Current hp drained×5 exp". The deeper you go, the longer and more exp costly it is to recover.

[illyahr]

The Maho-Tsukai from Oriental Adventures (Tainted Sorcerer from UA is the same class) allows you to use blood as a component and use your Taint score as your casting modifier for spell DCs.

The Pure Blood Magic feat from Rokugan Campaign Setting allows you to deal damage to yourself equal to the spell level of the spell to increase CL by one or DC by two.

[Blu]

Seems too prone to abuse... Especially by NPC's. Someone mentioned it before but since the the NPC's are expected to die, they don't care about long term drawbacks and the feat being tied to HD just means they can even pull out tricks far above the CR they are. For example, a 9 HD monstrous humanoid of CR 5 could pull out a lvl 5 spell out of this.
A 5th level spell against a party of lvl 5 PC's, like for an example a Cloudkill can be game ending.

And using the logic of a huge drawback compensates a huge power does not work, take the spell system implemented already on the system, they put on a strange and most of the times weird drawback(material and xp costs) thinking it would make spells OK. Didn't work, paying the XP cost of a Wish is worth it considering the effects.

And it was also pointed before, PC's will either ignore the feat or start thinking of character as disposable, since the feat pretty much does that for low and mid level play.

I would recommend changing the feat to a more short to middle term drawback and seriously limitating the feat in another way, especially to non-casters(or simply not allowing it to them). One idea is changing the drawback to damage to CON = spell level since it would balance it more evenly, make it viable to PC's and still have serious consequences.

[Captain Kablam]

So from what I gather in the consensus is this:

Blood Magic (Metamagic)
Some practitioners of the arcane have learned how to sap their very life's essence for greater, mystical power.

Prequisite
One must witness Blood Magic in use or have it be taught to them. Must participate in a ritual that allows them to use Blood Magic

Effect
For a permanent drain on the caster's vitality one can cast spells when they otherwise would be unable to. This includes not having the spell prepared or having used up all spells one could cast that day, and can even cast spells not on their spell list or barred by school or class restrictions, provided that one has the sufficient CON to cast such spells. The price paid is 1CON per the effective level of the spell being cast (ie: Level 1 costs 1CON, Level 2 costs 2CON, etc), and factors in the adjustment from metamagic feats. This damage can not be substituted with temporary effects such as Bear's Endurance, and cannot be recovered through rest, healing, or regenerative spells and can only be claimed through the use of a Limited Wish, Miracle, other similar sufficiently powerful spells, or a separate ritual and recovery of 100xp per CON point restored and one day of rest per point restored.

Additionally, if one uses Blood Magic one a spell they do know, the effect is empowered at no additional cost.

Is there anything else that should be accounted for?

[ATHATH]

You might want to clarify that undead and other creatures with CON scores of -- don't get to spam blood magic for free.

Can you use blood magic to cast a Miracle spell that could then restore the CON that you've lost from previous uses of blood magic?

[noob]

Miracle solving the effect of blood magic is not in the list of the effects miracle can do with no xp cost.
so while you could use miracle to cure the hp loss from blood magic the amount restored and the xp cost are not defined.(so it could possibly cost 10000 xp per lost con or another silly xp cost or maybe just 5000 for all the con drain but it is up to the gm)

[Fouredged Sword]

I would still suggest the recovery cost be a ramping cost, say 100exp per point currently lost to recover a point of con. Currently you have it so 9x100 or 900exp and 9 days of recovery can create a 9th level spell. A level 1 character on tbe cusp of level 2 can do that and recover in a week and a half. He will likely gain more exp with the encounter he solves with a 9th level spell than he loses. In my suggested method it would be 900+800+700+600+500+400+300+200+100 or 4700 exp. Pulling out a 1st level spell once per day is cheap. Casting a 9th level spell burns half a level for a mid level adventurer.