This is something I came up with a rather long time ago when I was pondering magic systems. Basically, I’m not too much of a fan of the spell slot system, espescially not in the later editions with their spell bloat. Frankly, I find the 100 page plus spell lists very tedious, especially when there are so damn many attack spells. Stop it with this glorified artillery stuff. Sorry for that rant. Basically I like my magic systems with a lot of utility and multi-function spells if possible, and not too many of them.
This is made for an OSR-style D&D, where HP pools go from sub-tens to around 30. If you are using a system with larger HP pools you might want to increase all HP based effects.
And really, when I was making this it escalated to being a full-blown class for Lamentations of the Flame Princess (it’s proably the retroclone I’m most familiar with). So yeah. Here it is as a PDF: Blood Mage. Below comes the spells in plaintext, if you want that instead. They could probably be ported to other systems pretty easily.
0. Transfusion [1 HP]
One of the simplest blood spells available. Draws blood from one person into another. Target two creatures, one which may be yourself. Move any amount of HP up to your level from one of them to the other. For unwilling creatures, you need to hit them with an attack for the spell to take effect.
1. Coagulation [2 HP]
Target a creature you can reach (including yourself). Heal them 1 HP, and stop any bleeding. If they were dying, stabilize them. Can be cast as a reaction when taking slashing damage, to halve the damage taken.
2. Blood Rush [1 HP]
Accelerates a target’s blood flow. Grants a +1 bonus on initiative, and a +2 to attack rolls and all saving throws except for Poison (for which the effect is reversed). However, the recipient takes double damage from slashing attacks, and bleed at twice the normal rate. Lasts 10 minutes. Can be reversed.
3. Blood Seeker [1 HP]
You can sense the location and general shape and size of any source of fresh blood within 600’ whether it’s inside a (living) creature or without. This effect lasts for around 10 minutes.
4. Crimson Arrow [3+ HP]
Launches an arrow made out of your own blood at a target within 80’. Make a ranged attack roll, at +5 against living targets (with blood inside). It deals 1d6 damage, plus 1d6 damage per 2 additional HP spent.
5. Bloodletting [1 HP]
Draws out the bad blood from a creature. Slash your target with a sharp implement (with an attack roll against unwilling targets), dealing 1d4 damage, and curing/removing any one disease, poison, or drug/potion effect.
6. Martyrdom [1 HP]
You imbue your own blood with power. For the next 10 minutes, whenever you take damage, any allies within 10’ is healed for an equal amount, shared among them. Can be changed as to damage enemies in the same way instead, chosen on when casting.
7. Serum Infusion [2 HP]
Duplicates one effect within your blood in your target, whether it’s a disease, an active potion, poison, or anything else. For any instantaneous effect, you can transmit it if it’s within one round from when it took effect. Unwilling creatures must be hit with an attack for the spell to take effect.
8. Crimson Weapon [1+ HP]
Summon forth any regular weapon, but made of blood. It works just as a normal weapon would, but is destroyed if you stop holding it. The cost is the weapon’s average damage, rounded down, but is refunded if you cancel the spell yourself.
9. Blood Regeneration [5 HP]
Forces a massive creation of new blood in a target. They will recover 1d6 HP per round, for 5 rounds. If the healing would bring them above their maximum HP, they must make a save vs. Poison or lose their next round in agony, as blood seeps out of every opening and pore.
10. Vascular Pressure Control [3+ HP]
Majorly increases the blood pressure of a living creature (with blood) within 50’. Roll 1d6, plus 1d6 per 2 additional HP spent. If this roll is higher than the target’s missing HP, they take the number rolled as damage, no save. Otherwise, they take no damage.
11. Sanguine Gift [2+ HP]
Transfer blood power to a spell caster. Restore a one of the caster’s spell slots, by taking damage equal to twice the level of that slot, +2. This requires a 10-minute ritual, during which the both of you sit still, taking no other action.
12. Invoke the Old Blood [5 HP]
Draw upon the remnants of the blood of the old gods. For an hour, each time a living creature is damaged within 100’ of you, you recover 1 HP. When this happens, you can choose to make a save vs. Magic. On a success, you learn something (anything) about the creature, but if you fail, you lose your next round in confusion, as the memories in their blood mixes with yours. There is a 5% chance on casting that this spell awakens a sleeping old god.