When you merge minions, the first that you choose on the merging screen will be the base. This means that it will have his ATK, DEF, SPD and other stats upgraded or downgraded. For example, if you choose a Pataimel and merge him with a Patalchu, the stats Attack and Defense will increase, since Patalchu has better Attack and Defense Growth Rates.
The second minion on the merging screen will be the secondary, having only minor impact on the result. This means that it will change the skin and 1/3 of the body of the base. Its stats however are completely ignored. Anyway it has impact on the result's Growth Rates, which gives it partial impact on the result's stats.
For info about how minion-specific variables change through merging, see:
Calculation of Appearance
A minion's appearance is based on their Merge Slots (ms for short). These are small component parts of minion's bodies. A pure minion's 48 merge slots are set to their ID. Upon merging, 32 of these ms of the base and 16 of the secondary are carried over to create the body of the resulting minion.
The result's ms are occupied with these ms:
Result's ms 1 to 32: ms of the base. Exactly (in order): 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 2, 8, 14, 20, 26, 32, 38 and 44. Result's ms 33 to 48: ms of the secondary. Exactly (in order): 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43 and 46. Also, the posture of the base and the skin of the secondary is attached to the result. The skin's tint is defined on the basis of the resulting Element Ratio combination.
The full formula for stat calculation requires:
- Growth Rate of the base
- Growth Rate of the result
- count of level-ups the base makes
- initial stats of the base.
The formula can be applied to every stat.
New stat = initial stat - (BaseGR/20) + (ResultGR/20) + level-up count * leveling bonus
Leveling bonus depends on the result's GR:
- Dr. Gil references the change in appearance of Minions after merging (and perhaps the lack of this feature in the second game) in the post-game of Jade Cocoon 2, saying "In the age of Cocoon Masters, I have heard of mutations just after merging...".