If you're going to get a BT, I'd put Witch on front row and BT behind it, because BT is weak to magic attacks. When Witch is getting low hp, switch BT to front.
If you're going to PvP alot, I'd suggest getting an Exo for sure, they're pretty much necessary for PvP now.
And also, just a heads up. A Spartan costs a TON of money to get and then upgrade. My Spartan costed me about 750m with full upgrades and maxed War Cry.
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