Could you say ideas that you think you'll keep (or seems interesting) ?

I don't like this idea.  Spells like what you have mentioned can imbalance the [vanilla] gameplay very easily.

Besides, it makes no sense at all. Charm = magical spell. Magical resistance protects a creature against magical spells. So basically this spell would ignore the creature's magical resistance?

- I agree that willpower and other stats should be taken into account. If you know your enemy can use this against you, counter spells and items are a must (though this currently IS just for roaming creatures).

- I can see per-turn mana costs adding data management overhead "why do I suddenly only have a max mana val of 5 when it was just 20?" But I can also appreciate forcing the player to make a significant, long term choice when casting it.

- I can see a 'timing-out' of a charm to be frustrating to the player, but understand the perceived necessity.  If the charm works, I don't like the idea of worry about it randomly un-working.  You'd have to be given fair warning, and perhaps the option of re-charming before the spell breaks.

- I like the idea of spell variations that alter stats...a 'Twist Creature', 'Soul-Crush', or 'Mind Domination' that givens bonuses and penalties to various stats of the charmed creature

All great feedback...gives a nice pool of ideas when we come back to polishing that feature.

If Stardock managed to reflect the Presence and Domination differences of Vampire: The Masquerade's disciplines, that would be awesome. Domination would be easy (take control, can end with the target losing its own initiative to act, needing direct input from the master) while Presence (Charm...) would be tricky as you don't really "control" the target (but it retains free will and can act by himself always).

I'd see 'Presence' as the simple ability for you to see through that unit's FOW.  That'd be pretty handy when keeping tabs on those wily Sovereign units

Nice trick.

Btw, if you do a maintince cost for a resource like mana - dont let it be deducted from the amount you have, instead reduce the total by that much.

Titan Quest did this for lots of abilities it made it much more fun to use. It was displayed as a solid 'used up' part of the bar - same mechanic but FAR more user friendly.

Its not exactly the same ofcourse but my point is what the player knows can make mechanics fun/unfun so good presentation is not 'icing' on the cake, its far more important.

Thanks for the reply

About willpower : it should be a stat used when you need to resist the spell and when you check for spell-end. Even if you control a strong willpower creature, it will have a greater chance of freeing itself.

Cost per turn : it shouldn't be different from the usual upkeep (gold or food or whatever ... if a "normal" spider cost 2 foods then a "charmed" spider should cost the same. Then if you want to control that archdemon who has an upkeep of 5 earth mana, 10 fire mana, 30 gold and 10 population per turn, then you have to prepare for such )

Timing-out : Why not warning the player when a charmed unit has over 75% (or even better :  a user-choosed stat) chance of breaking their binds ? Or something else : when a unit free itself, the unit will stay for one (or more .. depend on the willpower of tha charmer) round doing nothing. Then you have one round to try to charmed that unit again.

Altering stats : in fact control spells should be in 3 categories.

Total control : unit will never get its mind back, you just burnt it. But the controled unit has no brain, thus has less efficiency with brain-skills.

Domination : you control the unit, it's like yours, but has still its whole mind. You has total control, but domination will lessen with time AND with orders that are against its "way of life". Ask a spider to destroy a spider lair and it will have a great chance to fight the order. Order it to catch someone with their web and they will accept easily.

Influence : the influenced unit has lesser chance to strike your units, a chance to rebel each turn against it's owner and becoming a neutral unit (noone controls it), you'll spend less to bribe it, it becomes a spy for you, or talk to anyone how good you are (increasing diplomacy skill).

At least, some diplomacy tech should give you bonuses for influence. Military (or spell) should give you bonus for domination spell. Total control would need a fair level in life/death magic and civilization (how to keep alive something that has rotten from the inside)

Many have already voiced similar opinions but I'll just add mine as well to give it more weight.  The proposed system for charm is too simple.  You already have a magic resistance stat and this is the perfect place to use it.  It should be one of the major influences on the charm working.  Creature level or strength shouldn't.  For balance reasons I suppose it has to but I'd prefer seeing other ways of handling it.  Borrowing from another poster, a giant might be very strong but have a weak or gullible mind and be somewhat easy to charm for instance.  A zombie might be weak but would be completely immune.  I think you should also consider having special abilities enter in to this (I think you are going to have them, correct?).  For instance the Giant above could have the "Weak-Willed" ability giving a 50% bonus to charm spells (or any mental attack spell) against it.  The zombie would have the "Undead" or "No Mind" ability and be immune.  A system like this keeps things fairly simple and easy to understand but also allows for depth and flexibility.

What if there was no per-turn cost for roaming creatures, but if someone were to charm a player's units, they would have to have a per-turn cost, perhaps based on the opposing sovereign's power and/or targeted unit's power?

I also think the upkeep for charmed roaming units should be small or non existent.

This could be again one balance factor for small nations to help against larger nations.

Just think of a small magic kingdom which has charmed a large army and can now fight of the troops of much larger kingdoms.

Still this is a quite tough balancing topic. Maybe the upkeep should depend on the distance to the charmer???

This would offer smaller kingdoms a good opportunity, but is probably not easily traceable for the player, why he had one round an upkeep of 10 and the next of 20 by just moving a unit.

per-turn mana costs: Beside adding data management overhead, I do not see what kind of fun per-turn mana costs added to the game, especially if we are talking about a short term spell, charm, which only happen in tactical combat.

The better way is probably to pay the mana cost upfront, when you cast the Charm/Dominate spell.

When you cast "Charm them 2 turn" to 10 level 8 Trolls, it costs you 2*10*8 mana.  The UI tells you this cost when you mouse over the trolls.  If you agree to pay the mana cost, they are charmed for 2 turns.  The trolls will then gain a status of "Charmed 2 turns"

When you cast the same "Charm them 2 turns" to 10 level 2 spiders, you need to pay way less mana.   And of course, gamer can research Charm 3 turns, Charm 4 turns etc.  And there can be spells/equipment that reduces the cost of charming certain type of units.

any % for a charm to work is ok, the only issue is that on single player I would just save before I cast and then restart until it would work.  Then I would have a power house and stomp what I could.  I like the idea of a brake effect if you are low lvl and the creature is high lvl.  This way if I saved and restarted and eventually charmed the creature, it would only last like 1-2 turns, then I would have to go through the same hassle again when it broke.   That would make me think twice about charming it in the first place.  Especially if it wore off in a tactical combat, it would be a pain to save and restart 99 times lasting only 2 turns were the combat would take 5-6 turns.   

You can also restart the game until you have the perfect start position, make a mod that gives you an overwhelming advantage, or just plain use cheatcodes. All of these things can make the game a lot easier, and none of them are an 'issue'.

It is neither possible nor desirable to prevent such things.

Just to put it aside - obviously some monsters / armies have to have charm immunity / resist (resist can simply be added to monster level in calculation).

Several things:

1) To make level difference more significant you can use (Target lvl - Caster lvl) ^ X. you can tweak X or make it XML variable.

2) There has to be some upkeep for charmed monsters (mana / food / both)

3) a cool thing would be to charm your own troops - if you are low on resources but high on mana, use charm to reduce costs.