D&D General Thoughts on HD and Blood Magic

[SkidAce]

This is what I use for sacrificial magic, a modification of the rules in the A5e version of Adventures in Zeitgeist:

Sacrificial Magic

Any character with the Rite Master feat can potentially cast any spell of an appropriate level with the ritual tag. Additionally, any character with Constitution 13+ and Intelligence 5+ can cut themselves, bleed a copious amount, and meditate on their blood for ten minutes in order to cast a small selection of ritual spells. When doing this, the character expends any number of Hit Dice. More powerful spells require a payment of more Hit Dice, but the spells do not require any other material components, holy symbols, or spell foci (except those with a stated cost).

For two Hit Dice, they can cast augury.

For four Hit Dice, they can cast divination.

For five Hit Dice, they can cast contact other plane.

If the character has access to further ritual magic, it can be cast through blood sacrifice as well, on a one Hit Die per level of spell basis. Blood sacrifice can allow a character to cast a ritual spell they would otherwise be too low level to cast (a primary draw for the technique).

It should be noted that the blood sacrifice doesn’t have to be the caster’s blood. For sacrifices up to four Hit Dice, any creature’s blood can be used, with the understanding that a sacrifice equal to the creatures Hit Dice will kill the creature. Spells of 5th level or higher require a blood sacrifice of a sapient being to proceed. Doing so to an unwilling creature is an inherently evil act.

Where in Zeitgeist was the info you used as a basis?

 

[el-remmen]

What would you do if the character had multiple hd sizes from multi-classing?

They’d get to choose which they spend. I see no issue with that. They are still giving that up for other potential magical uses (many magical items in my games grant additional powers via spending HD*) or regaining HPs.

I personally enforce a lower HD replenish before bigger HD do house rule. But that is not necessary.

* for example one PC has a short sword +1 but he can spend a HD to go invisible (as spell, but no concentration) for a number of rounds equal to a roll of the die.

 

[el-remmen]

I will have to say however that both my groups tend to short rest as much as possible, so having fewer HD to work with matters to the table style.

 

[SkidAce]

I will have to say however that both my groups tend to short rest as much as possible, so having fewer HD to work with matters to the table style.

Mine short rest on occasion. So really I need to come up with a reason to use/or stockpile them*, otherwise the blood mage will just go nova.

Of course, I would then remind them that they only gain half back on a long rest...



*expend them all gain a level of exhaustion?

 

[Micah Sweet]

Where in Zeitgeist was the info you used as a basis?

I'm trying to find it, actually. I copied the material a while back into my compilation document, and now I can't find the original.

 

[Benjamin Olson]

I think rolling the hit die and subtracting it from an enemy saving throw that just succeeded would be the most fun, and about the only thing that would regularly be worth pursuing the path of blood magic over (other than just to be edgy). It might need to be coupled with proportional hit point loss and temporary reduction in maximum hit points to feel balanced.