yzak is a commander now but he did say that he was getting into some sort of trouble like court martial i guess in military terms after the war. the chairman spoke for them and i think thats why they got off and why he is fighting again cuz like i said he was a coucil member at the end of seed remember when he was wearing the green cloak that the council members wear. but watch episode 11 of gundam seed destiny about 15 minutes into it and you'll see what i'm talking about