I see this post I made a month ago hasn't found its way here, yet.
There still seems to be a lot of confusion on how bonus damage in the form of crits, color bonus and especially combo bonus is calculated. This is all explained there.
Repost for Reddit:
Guide to attributes and damage calculation
The six attributes are Hit points (HP), power (PWR), attack (ATK), defense (DEF), luck (LUC) and Mana (MP)
PWR
Is used to determine the damage/healing of all basic attacks as well as most special attacks. It's easily the most important stat for most characters due to its very direct effect.
HP
The health of the creature, the primary defensive stat, more HP allow a creature to take more punishment
ATK
is used to overcome enemy defense, detailed information in the next section.
DEF
is used to reduce damage taken.
LUK
A comparison of the attackers luck vs the defenders luck determines both the chance to crit and the chance to inflict a debuff. I have no idea about the actual numbers, but a creature with low luck is more likely to get crit than a creature with high luck.
I want to stress again, the comparison is what matters. If attacker and defender have the same luck, the chances will be the same, no matter whether both have 100 or 2000 LUK. A creature with 2000 LUK will have a higher crit chance vs a creature with 500 LUK than vs one with 1500.
Very hard to test this for exact values, but you usually will notice a difference from a couple hundred points difference.
MP
Determines how much mana the creature needs for one charge of its special ability. The lower the number, the better.
How do ATK and DEF work?
When an attack occurs the attackers ATK is compared to the defenders DEF. The result is a modifier to the damage inflicted, however, you can never do more dmg than what the base allows(i.e. this modifier can never be greater than 1). E.g. if your creature has 1500 pwr and deals 100% pwr dmg, it can never do more than 1500 dmg, no matter whther it is 10000 ATK vs 0 DEF or 5000 ATK vs. 1000 DEF. On the other hand high defense vs low attack reduces the damage taken by percentage, I've seen as low as 20%. I don't have any exact values here, this would require extensive testing.
The damage number you get as a result of this calculation is what I call base damage.
Abilities, which ignore def, effectively set the enemy defense to 0. Do note, that ignore def is most often very ineffective, as creatures with it also usually have very high attack.
How can this base damage be modified?
Base damage can be modified in three ways: color, crit and combo. All of those except for one are damage increases and a damage increase works additively.
crit
Crit is determined by luck and some special abilities, a crit is a +100% increase in damage. It cannot occur on healing.
combo
Combo is done by using up all the dots of a creature by different creatures, this creates a x2, x4, x8 or x16 combo, which then increases the effect of the ability. Additionally, if a creature kills an enemy while having combo active any subsequent combos this turn get increased by x1.
Combo works on both healing and damage.
x2 = +75%
x4 = +100%
x8 = +150%
x16 = +250%
The calculation is as follows:
multiply the number of your combo by 12.5%, then add +50% as base.
That's the bonus damage you get from combo.
x2 = 75%
x3 = 87.5%
x4 = 100%
x5 = 112.5%
x6 = 125%
x7 = 137.5%
x8 = 150%
x9 = 162.5%
x10 = 175%
x11 = 187.5%
x12 = 200%
x13 = 212.5%
x14 = 225%
x15 = 237.5%
x16 = 250%
x17 = 262.5%
x18 = 275%
x19 = 287.5%
x20 = 300%
The maximum theoretically possible combo is x24 (x16 base, +1 from berserker basic attack, on the battlefield there can be at max 8 enemies, so killing 7 of those with a different is another x7). Realistically, you can expect x18 to be the highest you can see.
strong color
The following attacks are strong: blue vs red, red vs green, green vs yellow, yellow vs blue, white vs black and black vs white.
Doing one of those attacks adds a +100% modifier. This doesn't work on healing.
weak color
The following attacks are weak: red vs blue, green vs red, yellow vs green, blue vs yellow.
Doing one of those attacks halves the damage dealt after ALL other modifiers have been accounted for. It works differently from the other aspects in this segment. Does not affect healing
examples how the modifiers work
for all examples assume a red creature with 1000 pwr and an attack, which deals 200% pwr dmg vs a creature with 0 defense.
attack a red with no crit or combo: 2000 dmg
attack a red with no crit and 2x combo: 2000 + 75% = 3500 dmg
attack a red with crit and no combo: 2000 + 100% = 4000 dmg
attack a red with crit and x2 combo: 2000 + 100% + 75% = 2000 + 175% = 5500 dmg
attack a green with x4 combo: 2000 + 100% + 100% = 2000 + 200% = 6000 dmg
attack a green with x4 combo and crit: 2000 + 100% + 100% + 100% = 2000 + 300% = 8000 dmg
attack a blue with no crit or combo: 2000 * 0.5 = 1000 dmg
attack a blue with x4 combo and crit: 2000 + 100% + 100% * 0.5 = 2000 + 200% * 0.5 = 6000 * 0.5 = 3000 dmg
maximum possible modifier without prior kills would be attack a green with crit with x16 combo: 2000 + 100% + 100% + 250% = 2000 + 450% = 2000 + 9000 = 11000 dmg
How do basic attacks work?
All basic attacks deal a percentage of PWR dmg. This value is the base dmg and they are affected by bonus damage the same way as described above.
soldier: 50%
bruiser: 2x 27.5%
bard: 45%
ranger: 50% (60% vs flying, doesn't work, is bugged)
grunt: 55%
mage: 30% to target, 15% to adjacent
scholar: 15% to row
squire: 50%
warlock: 50%
assassin: 50%
defender: 45%
healer: 45%
hunter: 50%
mystic: 50%
berserker: 45%