Certainly. 8D Uhh, okay, well... Raiden is the main character of Metal Gear Solid 2, and this actually caused a lot of grief among fanboys because they were like, "RAR, WE WANT TO PLAY AS SNAKE, WE DON'T CARE ABOUT THIS ANNOYING PRETTY DUDE WHO ALWAYS TALKS TO HIS GIRLFRIEND AND SHIT." annnd yeah. As for Raiden himself, he... did a lot of his training with Virtual Reality (VR) missions and so the first real field mission he goes on is the one that you play in MGS2 -- well, as far as he knows. It turns out that he was actually a child soldier who fought in a war in Africa, and was the adopted son of Solidus Snake (one of Solid Snake's brothers)... UHHH, oh, and he kind of hero-worships Snake to an extent, so he's a little down right now because Snake just died at Damned.

Does that help? HAHAHAH. XD;; Just let me know if you have any more questions?