Kind of a newb question but how many auras can a mercenary produce?

With gear they could technically have 4 but would all of them work?

Act 2/3 mercenaries can have 4 auras.
They would all work.
If same aura is delivered several times, levels are added.
Ex : Edge / Bramble act 1 merc delivers level 30/36 thorns.

https://www.theamazonbasin.com/wiki/index.php/Aura_When_Equipped

in practice, your char's auras need to be taken into consideration at merc too. and reverse.

so let's say you're a barb with a beast BA, or paladin, or bowa with faith ... then you don't need faith at your a1 merc. You don't need an offensive a2 merc either.

This post was edited by the_rest on May 5 2018 07:07am

Okay thanks for the replies.

I am using a vengeance/conviction paladin and wanted to equip a rogue merc with Ice, Dream, and Dragon so I could get Holy Shock, Holy Freeze, and Holy Fire. I'll be placing points into the synergies anyways for vengeance.

Holy fire/freeze/shock would only be active for your mercenary, not for you.
This is rather pointless.

A vengeance paladin (aka : 'avenger') needs :
Faith merc if attack speed is not at max,
Pride/Might or Reaper'toll/Might merc to get back mana (and life) with each strike. Vengeance costs a ton of mana...

Why would the auras only be active for my merc?

Because they are source only auras, example: holy fire is only used on Paladin when level 6 vs party auras, such as might when whole team can use it in the radius

There's no reason why. It's how the game works...

Ahhhh, source only auras... I guess I never actually played a paladin that used them. I assumed they were party auras. Scratch that idea, thanks for saving me some time haha!