What level might do the a2 mercs have?

[Jabal]

Does it increase as they level? What's the formula?

[Orphan]

Yes, it increases per lvl. Here's a little bit about the equation, but there's more to it then this:

INT((MercLvl-MercBaseLvl)*(SkillLvlPerLvl/32))+MercBaseSkillLvl

MercLvl = The merc's current level
MercBaseLvl = The merc's base level. For some mercs there's more than 1 entry in hirelings for them, so their base level will change once their current level reaches a certain number, more on this below.
SkillLvlPerLvl = A number representing the amount of skill they get per level, out of 32
MercBaseSkillLvl = The base skill level

Take the following example for instance:

Act 2 NM Defensive (Holy Freeze):
First Entry:
MercBaseLvl = 43
SkillLvlPerLvl = 10
MercBaseSkillLvl = 6

Second Entry:
MercBaseLvl = 75
SkillLvlPerLvl = 0
MercBaseSkillLvl = 16

So after the Act 2 NM Defensive Merc reaches lvl 75, he'll stop gaining skill levels, but let's do a run through some slvl's:

Level 50 Act 2 NM defensive merc:

INT((MercLvl-MercBaseLvl)*(SkillLvlPerLvl/32))+MercBaseSkillLvl
INT((50-43)*(10/32))+6
INT(7*0.3125)+6
2+6
Skill Level = 8


Level 55 Act 2 NM Defensive Merc:
INT((MercLvl-MercBaseLvl)*(SkillLvlPerLvl/32))+MercBaseSkillLvl
INT((55-43)*(10/32))+6
INT(12*0.3125)+6
3+6
Skill Level = 9


Level 70 Act 2 NM Defensive Merc:
INT((MercLvl-MercBaseLvl)*(SkillLvlPerLvl/32))+MercBaseSkillLvl
INT((70-43)*(10/32))+6
INT(27*0.3125)+6
8+6
Skill Level = 14


Level 75 Act 2 NM Defensive MErc:
INT((MercLvl-MercBaseLvl)*(SkillLvlPerLvl/32))+MercBaseSkillLvl
INT((75-43)*(10/32))+6
INT(32*0.3125)+6
10+6
Skill Level = 16


Now the merc has reached 75, so he'll use entry 2 in hirelings. Entry 2 has a skilllvl increase of 0, thus his aura isn't going to increase anymore from lvl 75 onwards.

I'm not going to list all the base levels, skill level increases, etc as there's quite abit of them in hirelings. If you have ATMA, there's a hirelings.txt file in it's config directory. If you wanted to, you could instead go to http://forums.diabloii.net/showthread.php?t=304163 and under the heading "Merc Stats and Leveling Mercs" there's a spreadsheet with all the merc stats per level.

[Orphan]

Can't edit my above post, but the information you need for Act 2 Might merc are:

---------
First Entry:
MercBaseLvl = 43
SkillLvlPerLvl = 8
MercBaseSkillLvl = 7

Second Entry:
MercBaseLvl = 75
SkillLvlPerLvl = 8
MercBaseSkillLvl = 15
----------

When I initially read your post, I thought you were talking about all merc skills. Use the information here similiar to the holy freeze example.