OK so we have a giant. He is 9 feet tall and has a little over 30 times the strength of a man and is heavily armored so he isn't afraid to go (but generally doesn't go) waist deep in the enemy, he will be engaging with normal sized humans and other creatures close to his size or larger but not nearly as strong (maybe 2/3 his strength max). Because of magic you shouldn't worry much about material strength for the sword, feel free to design a weapon or find an example.
P.S. I know blunt weapons are preferable but for many reasons I wish for a sword. And it should be a two hander or at least a hand and a halfer. And specifically i am looking for a weapon for hewing through enemies through shear power. He weighs roughly 700-800 pounds fully armored although he is still agile as the average elite trained fighter since he doesn't lose speed