Yes, there are 5 minions in all; Imp, Voidwalker, Succubus, Felhunter and Felguard. However, there are only three of them I always use in Battlegrounds. Here are the minions and the reasons why I use them:

1. Felhunter – There’s the theory that Felhunters are good on PvP realms, and are sort of useless on PvE realms. This is somewhat true… Felhunters have the Tainted Blood skill, which reduces the targets’ attack power. It can stack up to five times. Curse of Recklessness is a good add-on with TB.
2. Imp – Fire Bolt. That is all there is to it. When I use Imp in PvP situations, it helps. Using your Imp’s Fire Bolt and your Shadowbolt or Soul Fire, will turn you into a mage: Two Shot Goodness. Of course, DPS skills helps.
3. Succubus – My least favorite minion for PvP. She is good for Seduction, but for everything else…you might as well just use fear. Most of the time Seduction will fail and the Succubus will eventually run out of mana, but a chance of Seduction being cast is better than releasing your spirit. *cough*DPS*cough*

Hmm, maybe I should learn to play Warlock more. This is what I have learned so far, being level 66. Since I’m affliction, I do not have access to a Felguard. All of the Warlocks I have faced in the Battlegrounds have Felguards. That doesn’t stop me; don’t forget Banish and good old fashioned DoT (on the other Warlock, of course).