I have three questions.

Q1:
exp distribution after battle
I have found some basics on exp distribution in this thread.
/the_tavern_strategies_and_rambling_conversations
30% to hero (can be multiplied by Wizard hat)
28% - equally to each unit (summoned too), based on turns alive/turns total
42% - based on activity(summoned too) * Casting spells is not regarded as activity here.

Now I'd like to know a little more detail.

Provided that I clear a location(battle) solely on my hero's casting spells, how much exp do my hero or his units gain,
if my squad consists of

a)only hero ;
does he gain 100% exp?

b)hero and a unit(shaman);
how much exp do they each gain? My guess is 51%(30+42/2) for hero, and 49%(28+42/2) for shaman.

c)hero and two units(a shaman and a barbarian);
My guess is 44%(30+42/3) for hero, 28%(28/2+42/3) for both unit.

Q2:
I heard that my karma changes based on the alignment of units I hire.
My understanding is;
Decent +1, Good +2, Champion of Light +3
Unscruplus -1, Evil -2, Evil Incarnate -3
to my karma.
Is this correct?

Q3:
Chance to aquire neutral provinces through negotiation
I can virtually "bribe" Magical Forest neutral province for 50 gems, when I have Lv3 Diplomacy skill and positive karma(more or equal to 0). Diplomacy really helps. You can see more on this thread.
/diplomacylooting

Some things are not covered even in that thread. So let me ask my question.

a)Sometimes I can take lizardman land without fight through negotiation. Sometimes I am forced into battle even if I try to negotiate. What makes this difference?

b)How can I negotiate to aquire Medusa lands? Since there are Medusa guards available for human player, there seem to be some chance to bribe them.

Actually the Main reason I bother with the diplomacy skill is so that I can get Alliance with the Elves. I find these the most difficult provinces to take otherwise due to the armor piercing, flaming and double shots of the Elves plus the Peggys and Unis.

Dwarfs and Halflings easily taken by Scout or Mage. Centaur and Nomads taken with Solo Fighter. High level Gob, Lizzie and Giants usually taken with Mage.

Also Diplomacy gives discount on stuff in the stores which is good for me as my Scout can then pick up gear for the Warrior on the cheap. Not to mention scrolls as well. I think Dip lvl 3 gives a 40% discount and lvl 4 and 5 each give 20% more.

Thanks for your comments. I see your points.
Yes, Elves are tough. It is hard to win without lots of casualities.
Other than forming alliance with them, my solution would be growing up my mage to high level.
With the help of Phantom Form, he can go solo and clear elves with Fireball.
I came to think that Mage should go solo as soon as possible to obtain such a high level fast enough.
That is why I asked about exp sharing details in my OP.

12 Medusas are even harder than Elves to win without casualities.
Even if you have Lv20 mage, you will still need Tier4 spell.
Poison immunitized warrior seems to be the only alternative here.
And again, that is why I asked about negotiation with medusas. Diplomacy gives discount bonus flat 10% per skill level.
Those figures you mentioned are bonus for completing quest.
Diplomacy is still a useful skill without these bonuses, though.

By the way, spell Enslaved enemies seems to leech exp like summoned.
If so, I had better omit this Tier4 spell.

Sorry,i bump the thread to ask some related questions for that original post is a bit old.

About 42% in exp distribution,can someone explain it in detailed examples?

If i have a hero and a unit (the unit stands still without doing anything) in current army:

When my hero scores a melee kill ,is (30%+28/2%+20%) exp ensured or...?

http://www.gog.com/forum/eador_series/the_tavern_strategies_and_rambling_conversations/post60

42% - based on activity(summoned too)
UnitActRating = 20*MeleeKills + 10*RangedKills + 2*MeleeDamage + RangedDamage + DamageReceived + 3*SpellsStamina + 2*UsedHealing + UsedStamina + 1

So, your unit will have 1.
You hero killed 5 enemies in melee, 20 hp each, took no damage and had weapon with "tireless" attribute: 20*5+ 2*100 +1 =201.
Summary 202 activity points.
hero will get 201/202 of 42% exp.
unit will get 1/202 of 42%.

In this situation hero will get (30 +28/2 + 201/202*42)=85,8% of exp.

Ok, i get it.

Thank you,Gremlion.

Maybe I should open a new thread to give you" SOLUTION",but i forgot it,sorry.

Thank you for your follow up.

There are two stamina related elements in the formula.
3*SpellsStamina
UsedStamina
Are these elements applied to hero spell casting, while none of these kill/damage related elements are applied to hero spell casting?
If so, do they stack together?
eg., when casting a fireball spell, 3*4(as SpellsStamina) + 4 (as UsedStamina) =16 UnitActRating?

SpellsStamina applied to caster units too (curse from shamen, for example)
UsedStamina - total used stamina,
Most probably they stack.
Damage and kills from spells doesn't matter in activity rating.

There was person who dig up most of internal functions by bla-bla-technical-babble.
He also noticed that in 1.03 version spellsstamina does count for total activity rating but doesn't count for individual. I don't know is it fixed or not.

You've inspired me to look into this, and I've just found the XP calculation code. Yes, the bug is fixed, the calculation is definitely correct now. And yeah, UsedStamina and SpellsStamina do count together for casting spells, so it's 4x the stamina used for spells in total.

Can you look into medals?
Particularry interested in these:

Hero's cross
Battlemage's Badge.
Fire pennant

Funny, the code for medals is right after the activity calculation. It was a little tricky but I've already figured the first one out, no more need to make the author give up that information under torture. :)

Hero's Cross:
MeleeKills + RangedKills > 4
DamageReceived >= MaxLife * 2 / 3
Random(11 + MeleeKills + RangedKills) >= 13

Hopefully the other two won't rely on obscure values.

Here are the other two:

14) Battlemage's Badge
SpellsStamina >= 3
RangedKills > 0
Random(10 + SpellsStamina + RangedKills) >= 10
Random(NumBattlemageBadges + 1) == 0

15) Fire Pennant
Ammo > 2
RangedAttack > 0
RangedDamage >= RangedAttack * 3
MagicShot == 0
RangedKills > 1
DamageReceived >= MaxLife * 2 / 3
Random(21 + RangedDamage + 5 * RangedKills - 3 * RangedAttack * Ammo) >= 30
Random(NumFirePennants + 1) == 0

It really is "RangedAttack * Ammo", BTW, not "RangedAttack - Ammo".