So, I have been fighting these guys for like a day and a half, and so far I have only captured Lightning. So here's my question, since its easier to kill Amodar first, what if I get him first then Lightning? Does the tamable monster depend on which one I kill last or doesn't it matter?
I have reason to believe that by killing one of them first, you negate the possibility of retrieving his/her crystal/rare item. This aroused my suspicion when I was desperately trying to get Lightning's crystal and item. I always destroyed Amodar last, and kept on getting HIS things, so I decided to finish him off FIRST and right off the bat I received both Lightning's crystal and item.
Of course it must also help to be on Normal like I was, and this is just a hunch.