first time!? now you have me curious..haha
I'll have a look around when I get home this evening - makes me happy that there is (possibly) some exploration involved
While you "can" kill that first big guy, you don't have to, it's more of a "test your skills" type boss that you can bypass.
You can come back to this area later on in the game also.
Also regarding the dodge, your dodge is affect by your character stats and equipment you are using.
The heavier your gear the slower you are, etc.