So this guy couldn't save his friend, because he was weak and stuff. Years later decides to join the military with a jacked dude named Zack so he could save people. In order to join you have to be dipped into some memory juice that makes you stronger. He ended up being incompatible with the juice and lost his memories. Basically making him a vegetable with a personality disorder. Imagine recalling a memory of seeing someone do something, and telling some stranger that YOU did that even though you didn't, but your brain thinks you did? So yeah this guy lies... ALOT.