All spells that use blood magic have to be unlocked by researching this school. If your nation has any blood mages, you will want to do some research here. - Illwinter.

While the other schools of magic can at least pretend to have productive uses outside of causing death and suffering, Blood magic is more straightforward about its purpose. Rather than being powered by gems, blood spells and rituals are fueled with blood slaves, harvested from province population by blood mages at the cost of unrest and thus gold income. Balancing this shadow economy in addition to the normal complexity of Dominions is difficult and part of why blood nations are not recommended for beginners.

All spells that involve the blood path and the sacrifice of blood slaves belong to the school of Blood magic, although there are useful blood items that can be unlocked by researching the school of Construction.

Blood magic is incredibly versatile, allowing its users to inspire terror in the hearts of their enemies, open gates to the five Hells, start the vampire apocalypse, and so much more. Since the currency of blood magic is not dependent on site searching luck, it has the potential to scale far beyond what any other path can manage. During the midgame, competitive nations may have an income of 20/turn of any one type of gem, while true blood nations can easily be hunting 200-300/turn, rising to 400/turn by the late game. Well-run blood nations can flood the world in a tide of powerful summons, from the Ozelotls of Mictlan and Xibalba to the Se'irim called forth by Gath.

In combat, the majority of blood spells require a sacrifice and cause a good deal of fatigue. The power of these spells often matches their cost, however, especially when eliminating tough single targets through spells like Leech and Life for a Life. Blood can also mitigate its own fatigue through the use of special communions called sabbaths, as well as the handy Reinvigoration spell which clears fatigue from the caster and any communion slaves. Blood magic has further applications as a buffing path (Rush of Strength and Hell Power) as well as a source of morale plays (Agony, Blood Rain).

In terms of rituals, pure blood has great spells for removing crippling afflictions and old age to prolong a caster's usefulness. It also has significant summoning potential, from binding lowly Imps at low research levels to conjuring deadly Demon Lords at high research levels.

• Fire lets you use Blood to call Devils from the Inferno. With enough research, it can be used to banish a foe there in the midst of battle, or even to summon one of the five Arch Devils. It also lets you use Hellfire in battle, and can be used to boil blood without Blood Slaves.
• Air lets you use Blood to call Storm Demons, powerful & mobile Demons, from the Tempest Realms. It can also be used to uncork Pazuzu's wrath on distant provinces.
• Water lets you use Blood to call Frost Fiends, powerful ice-firing Demons, from the Icy Realm of Kokytos. With enough research, it can be used to banish a foe to that hellscape in the midst of battle, or even to summon one of Kokytos's six masters.
• Earth lets you use Blood to call Demon Knights, hellish & well-armed Cavalrymen. It can also bring power to the dormant Earth to serve you, tainting it in the process.
• Astral power is the "currency" of all Magic except for Blood Magic, but Blood can still add dark power to the Astral wellsprings and draw the Astral Plane's worst Horrors to the caster. See Horrors & Horror Marks for more details.
• Death lets you use Blood to bring Undeath to living beings without killing them, turning them into Vampires. It can also summon Bone Fiends, the skeletons of Demons who have died of old age.
• Nature lets you use Blood to facilitate unholy unions of the different species of the world (Cross Breeding). It can also feed and/or taint Nature directly, and can be used to Purify Blood in battle.

While generally not as thematic as national blood magic, generic blood magic still offers a variety of powerful tools to the enterprising blood nation.

Add combat, ritual spells

Many blood items are also very useful. Although they are unlocked by researching Construction rather than Blood magic, they are still relevant for blood nations.

• Construction 4 1 for 5: Flesh Eater
  Aside from its high damage attack and chest-wounding ability, the Flesh Eater is also notable for making the wielder berserk when damaged. This allows thugs to follow scripts at the start of battle and then take advantage of berserk later on.
• Construction 4 2 for 40: Lifelong Protection
  Lifelong Protections are useful in almost any context. The Imps can protect mages from assassins, swamp counterthugs, disrupt enemy lines in combat, and more.
• Construction 4 1 for 5: Sanguine Dowsing Rod
  Greatly improves the blood hunting abilities of 1 mages, less efficient for more skilled blood mages.

In addition to the blood magic available to all nations, several nations have unique blood spells which often overshadow the generic options.

EA Lanka
Lanka has a large roster of demon-ogre summons, as well as an efficient blood hunter (the Raktapata) to run the blood economy needed to summon them. Summons run the gamut from hard-hitting frontline troops (Rakshasa Warrior), to a heavy thug (Dakini) and even a potential supercombatant chassis (Mandeha). Monkey nations in later ages (MA Bandar Log, LA Patala) retain these summons, although they lack native ways to blood hunt.

Mictlan and Xibalba
The two Mesoamerican-inspired nations share most of their blood summons. A particular highlight is the Ozelotl, a troop which can be efficiently summoned with only Blood 4 research and is a flying, sacred murder machine with 3 attacks. In the Middle Ages Mictlan loses blood hunting but retains the summons, while the opposite occurs for MA Xibalba. In the Late Ages both nations regain their full blood hunting capabilities and summon roster.

EA Hinnom and later incarnations
The Old Testament-inspired nations have a small but potent roster of blood summons, though MA Ashdod has no blood hunters and EA Hinnom's are extremely expensive. The excellent Se'irim are a cheaper version of the Ozelotl, losing flying but retaining the sacred tag and killing power. Also of note is Release Lord of Civilization, a Blood 9 spell that summons one of several extraordinarily powerful mages (although Blood 9 is often too late to be relevant in multiplayer games).

Due to its Hinnomite influences, EA Berytos can also call the Se'irim. Furthermore, it is able to use blood magic to summon its own Melqart heavy thugs!

MA Ind is possibly the most bloody nation of the Middle Ages, but its only national blood spell is Release Lord of Civilization.

EA Niefelheim and later incarnations, LA Vaettiheim
These Nordic nations can cast the Illwinter global, which plunges the world into perpetual winter. MA Jotunheim and LA Vaettiheim are also able to summon Niefel Jarls with Winter's Call while Illwinter is active. Perhaps more significant than the summons are their effectively national specialty of Skratti turbo communions, which can fuel endless Horde of Skeletons spam.

EA Abysia and later incarnations
The Abysias have varying degrees of blood hunting ability. Their only national blood spell is Infernal Breeding, which summons much stronger spawn than the generic Cross Breeding would; they otherwise rely on the generic tools available to all blood nations.

LA Marignon
Unlike its Middle Age predecessor, LA Marignon is a blood nation that specializes in summoning demons. In addition to discounts on Soul Contracts and Lifelong Protections it is able to summon 333 Fallen Angels, powerful and affordable mages which can cast big battlefield magic and break Marignon into moderate death.

LA Ulm
Like Marignon, Ulm also transforms into a blood power during the transition from the Middle to the Late Ages. It has only one blood spell, Sanguine Heritage, but it is quite affordable and can be cast without any research (though LA Ulm lacks native access to the requisite crosspath)! It summons one of several unique, immortal Vampire Counts, discounted Vampire Lords with their own special abilities.

LA Pythium
LA Pythium's blood hunting abilities are rather limited, available only via 10% of Revelers. Their only unique blood spell is the low-research Orgy, summoning a Satyr commander which freespawns Maenads for hordes of potential chaff.

MA Na'ba
Although Na'ba lacks recruitable blood hunters, it can summon them in the form of the 11 Ghulah. These can form the basis blood economy to fuel Na'ba's more powerful blood summons, the Ifrit and Shaytan.

The following nations are all able to recruit blood hunters to some degree, but lack national blood spells:

• EA Sauromatia
• EA Helheim
• EA and MA Vanheim, LA Midgård
• EA and MA Pangaea
• MA Vanarus and LA Bogarus
• Any nation which has captured a Garnet Amazon province (Garnet Sorceresses)