Shulk appears to be the protagonist in Xenoblade. On his page, he mentions trying to unlock the power of Monado, the name of the sword and temporary title for the game in the West. Fiorung, the only female character in the group, says she wants to fight alongside someone. Dunban once wielded Monado, defeated the Kishin army, and is regarded as a hero to the Homs.
There are more characters in Xenoblade. The official site has slots for seven characters, but only revealed these three.
Xenoblade is due in Japan on June 10.