Force is about balance, fairness, consensus, and both the making and enforcing of contracts. Magic generally deals with bending the natural laws that men and gods generally agree ought to govern the world. (The reality of Erebus is more inter-subjective than it is objective.) Force prefers to enforce the rules, and thus counter magic.
The only beings that we know serve Dagda are the Runewyns and the Cipi. The Runewyns are winged angels that are immune to all magic, and can drain away most magic with a single touch. They are typically given the duties of crossing magical boundaries and assassinating powerful wizards who threaten to upset the balance of the world. The Cipi, also called the "Pillars of Creation," are seven giant true angels who guard the boundaries of Erebus against intruders from other planes and are responsible for enforcing the laws of physics.
Kael did at one point state that a good example of a Force spell is creating an impassible wall of force, which he said becomes impassible because of a consensus that the boundary should not be crossed. The Elohim world spell Sanctuary would fit this sphere well, although it is probably too powerful for a regular spell. Perhaps a version of that spell with a shorter duration would make a good Force III spell though, if it required sacrificing the caster or at least the prerequisite Force III promotion. (It would be far too powerful if it could be used every turn.)
One thing I think would be quite nice as a force spell is preventing other players from withdrawing from or renegotiating diplomatic agreements. I don't think that the code really allows that though. Forcing enemies to negotiate would also be quite nice, but just as hard to code. Moving Cordindale's Peace spell to Force III is probably as close as we could get.
Generally I think that as far as game mechanics go this sphere is better implemented as a counter against other sorts of magic.
You are welcome to borrow my modmod's spells if you like:
Force I: Temperance: Grants living units in the same stack the Temperance promotion, which provides resistance to both Holy and Unholy Damage.
Force II: Magic Resistance: Grants living units in the same stack the Magi Resistance promotion.
(I had made it so that Magic Resistance could no longer purchase this through xp. For my next release I decided to get rid of that spell, go back to the old way of getting this promotion, and introduce the following replacement)
Force II: Ring of Warding: Creates a Ring of Warding building in the caster's city. (As with spells like Hope, the caster needs to stay in the city to maintain the building. The building uses the same graphics as the Ring of Carcer improvement, but is made bigger to encircle the whole city.) This provides +25% defense (like Wall of Stone, which I am removing and replacing with Diligence, a building which boosts the
% and
% ), +25% magic resistance to units in the city, and (through an effect that uses the python prerequisite of a dummy spell) prevents any hostile summons nearby from being able to attack. (At first I made it kill said summons, but some thought that was too powerful. Now it gives them the Charm promotion, so that even summons with Blitz cannot attack. It also deals damage to them, with a cap based on how much mana you control.)
Force III: Summon Runewyn: A Runewyn is an Angel with the Flying and Magic Immune promotions, as well as both Demon Slaying and Angel Slaying (a promotion my modmod introduces). They also use the BtS ability (this does not work in cities) to target UNITCOMBAT_ADEPT and UNITCLASS_ARCHMAGE (as well as the various arcane heroes) in stacks of stronger units , and have a PythonPostCombat call that removes all of the spell sphere promotions from their targets whether they win or loose. Their art is that of a monochromatic re-skinned Angel of Death, with the symbol of Scales on its chest, the back of is robes, and seven times on the blade of its sword. (In my next release, this call also makes them cast Dispel Magic and when they are attacking a city removes any spell buildings it might contain. ) I gave the unit a base strength of 7 and 3 affinity for Force Mana originally, although for my next release I reduce the affinity to 1. I also made it so that the Ring of Warding does not effect them.
Dimensional I: Escape
Dimensional II: Unsummon: kills all hostile summons nearby
(This was deemed generally not useful, as summons generally have only one turn of duration anyway. In the next version replaced it with: )
Dimensional II: Sever Soul: Creates an invisible Severed Soul unit, which can explore on its own and can be sacrificed to call its summoner to its current position. (The spell was of course formerly unique to the Divided Soul unit, and in previous versions of my modmod instead dependent on the Soul Spillter I gave said UU so that the ability could be retained by upgrades. Now I just give Divided Souls Dimensional II.) Unlike the Base FfH2 versions, my severed souls are permanent summons. I switched to creating them through python so that they do not start out immobile. They are not flying, but can move through impassible terrain as well as rival territory. They can investigate cities. They get certain promotions from their summoner, like Mobility and Sentry. They are given unique names ("Soul of ___") to identify what unit summoned them. I recently gave them some combat strength as it seems necessary in order for them to have the command to explore automatically, but they are still defensive only.
Dimensional III: Summon Rift: This summons a unit which is like an ICBM from vanilla civ, but can also carry other units as cargo. It can deliver whole armies almost anywhere on the map (just not too close to units or territory of units of rivals with whom you are at peace) in a single turn.
(Since the AI never seems to use them as transports, I also included: )
Dimensional III: Rift Gate: creates a requires-caster building that functions as an obsidian gate.
Creation I: Muse: Creates a requires-caster building that adds culture, specialist slots, and boosts the gpp rate.
Creation II: Fertility: Creates a requires-caster building that provides free food and health.
Creation III: Abundance: Creates a requires-caster building that eliminates unhealthiness from both population and buildings.
I don't let this be built on raw mana, only on creation mana. Creation mana is added to a random tile on the map during the Amathaon constellation event.
Anyone can build Ice nodes in recent versions, but doing so is very slow.
I was just about ready to release a new version with the new spells, but since Tholal released More Naval AI version 2.4 today I intended to merge my modmod with that first. I'm thinking that Christmas Eve is my most likely release date now. If you wish to borrow my spells before that I could send you the code.