You enchant a non-wizard unit, sapping its strength. It gets -1 moves, -25% damage, and at the beginning of its turn, you drain 12 of its hitpoints and gain half of that yourself. However, like poison, this cannot kill a unit. The unit can escape the effect by being more than 6 hexes away from you at the end of any turn.
You enchant a unit to sacrifice its allies' health to save its own. Whenever it takes damage without dying, most of that damage will be healed while nearby non-Dark-Pacted units take that much damage instead. The more hitpoints they have and the closer they are, the more damage is diverted.
You permanently corrupt most hexes in a diameter-5 circle around the target. Units on the corrupted hexes become poisoned at the end of any turn. This spell affects at least 70% of the hexes in the area, chosen at random, but favoring hexes that are not yet poisoned (so a second casting reliably fills the remaining area). Poisoned ground is visible through fog and makes some cosmetic changes to the terrain.
You transform into a spirit. You retain your hitpoints, and your spirit form has nine moves. Otherwise, you have the stats of your new form. At level 2, you can become a Wraith or a Shadow; at lower level, you become a Ghost, and at higher level, a Spectre or Nightgaunt. You cannot cast spells while in spirit form, but you can return to your normal form at any time for 1 AP.
You summon an AI-controlled Walking Corpse onto each adjacent empty hex. They choose a random variation, partially depending on the terrain where they appear, and can attack the same turn they're summoned (and also move if you didn't summon them into an enemy zone of control). They are aggressive and always fight if they can; otherwise, they wander randomly unless they can capture a village or go for healing in one turn. These 'swarm' units move at the end of your turn, and during your turn, they are partially nonexistent, so that they don't get in the way of moving your regular units.
You enchant your default melee attack. The next time you kill any unit on offense, you reanimate it on your side with (half plus 10) of its max hitpoints. If it wasn't undead before, it becomes an undead version of its unit type. While you hold a Reanimating Touch, you can also use it on your own or allies' units for 6 AP. (If you reanimate an ally's unit, your ally retains control of it.
You kill a unit and bind its soul to yourself. You can't bind an enemy with more HP than twice your Necromancy rank, but you can bind any ally. Each soul grants you some of the abilities of the unit it once was:
Your current and max hitpoints increase by 1/4 of its max HP.
If it has a beneficial weapon special in melee, you gain that special, although berserk is limited to three rounds and you can't stack charge, berserk, and drain (instead, you get separate attacks with each).
If it has an ability that improves its own damage, resistance or healing, or reduces enemies', you gain that ability.
If it has an ability that helps allies in those ways, you gain a reversed version that harms enemies instead. A reversed healing ability acts at the end of your turn, and can't kill (like poison).
If it has an ability that affects the time of day, you gain a darkening version of that ability.
In a notable exception, you cannot gain any invisibility, skirmishing or teleporting abilities.
If it's a wizard, you gain its mana income.
If it's a wizard who already bound souls, you get all those souls.
You also gain XP for killing the unit, even if it's an ally.
You die and return as a Lich. When you complete the ritual, an immobile Crypt unit appears in your place, and as long as the crypt survives, you will reappear next to it at the beginning of your turn after any time you die. As a lich, doing a normal attack costs only 3 AP. When you become a lich, your living alliances (if any) abandon you, although you may keep any units you have already recruited, and you regain any skill points you spent on them. If your crypt is on a keep, it can recruit undead on your behalf. You can cast Renounce Life again to move or replace your crypt.
You twist the bones of a long-dead dragon into a semblance of life. It is so powerful that you must continually spend your energy to keep it active; on any turn when you do not cast Command Dragon Bones for 5 AP, it loses its moves, attacks, retaliation, zone of control, and upkeep until your next turn.
Command Dragon Bones: 5 ap, range 9, You activate a Skeletal Dragon for one turn.
You enchant the adjacent enemy unit to move to your chosen target and possibly attack. (You can only cast Compulsion when there is exactly one enemy unit adjacent to you.) It will proceed to the target by the shortest path, and then, if you targeted a unit, it will attack that unit with whichever attack does the most damage. You can make it attack a unit on any side; while moving, it is subject to your enemies' ZoC and not to your allies'. If the unit would have to pass through fog or shroud, you may attempt to cast Compulsion; this will clear the fog/shroud, but if the unit still can't reach the target in one turn, it doesn't move at all. Compulsion doesn't work on wizards or dragons unless you're at least two levels higher than them.
You enchant all adjacent non-wizard allies. They become unkillable undead; if they are reduced to 0 HP, they return with 1 HP at the end of your turn two turns later, or the next time the hex is empty. They become killable again if you die, even if you will respawn as a lich.