Mgoblue201
Won't stop picking the right nation
It seems that you have to wait until your sword gets struck by lightening. Sometimes it happens right away, sometimes not. I don't know if it's luck, or I need to do something to make lightening strike. I'll get hit three times before a lightening strike sometimes. I've probably done this fight 10 times now.
You can also use the shield bash move to block three of his attacks in a row, which leaves him open to a quick sword strike. It only took me three attempts to beat him using this method, but it does require timing.