reese said: Tagged black-tri-stars because that Zaku II is painted in the Tri-Stars custom colors.
I don't see any of the characteristic markings, though. And since there's only one of them here, there's really no reason to think it's more than just a black-and-purple Zaku.
Besides, the B3S never piloted Zaku IIs. They went straight from Zaku Is to Doms.
Actually they piloted Zaku II High Maneuver types before being given the Dom. I believe this occurs in a side story. There is also the MG Zaku II Black Tri-Star Custom to consider as well.
