The nameless Hero, also called "Eight" by the developers and some fans, is the main character of Dragon Quest VIII. Throughout the main story, all that is revealed about him is that he was an orphan taken in by the King of Trodain, and grew up to be a castle guard. He was also good friends with the Princess as a child.
The story starts out with the evil Dhoulmagus casting a curse on Castle Trodain. All inhabitants are turned into seemingly lifeless thorns, with the exception of the king, who was turned into a troll; the Princess, who was turned into a horse; and of course our Hero, who remained in his human form. Throughout the main story, it is never revealed why the Hero was left unaffected by the curse.
During the ending of the game, Princess Medea has to marry Prince Charmles of Argonia. The Hero, his friends, and even the King of Trodain, however, don't agree with this, and decide to help the Princess escape to Castle Trodain, where the Hero and the Princess live happily ever after. After the ending is viewed, a scene is shown where the Hero finds the gate to the realm of the Dragovians, a race of people who are able to turn into dragons. The player then has the option to save their game, and once they load their newly saved game, they now have to option to not only fight the final boss again, but also visit the realm of the Dragovians.
As the party stands in front of the gate to the Dragovian town, Munchie, the Hero's mouse who has accompanied him his entire life, leaves and slips under the gate. The gate is then opened by an old man named Chen Mui. The Lord of the Dragovians has gone mad, and Chen Mui asks the Hero for his aid to defeat him. If the Hero succeeds in defeating the Lord of the Dragovians, Chen Mui promises to give a full explanation of the Hero's background.
Once the Hero has defeated the Lord of the Dragovians, Chen Mui reveals that he disguised himself as Munchie the whole time to watch over the Hero, who is his grandson, and a half-Dragovian. This also explains why the hero was left unaffected by the curse, as the curse only affects human beings. He then goes on to explain that his daughter, Xia, escaped from the Dragovian realm long ago married the long lost Prince of Argonia. Chen Mui, however, did not approve of this relationship, and took his pregnant daughter back to the Dragovian realm. The Prince followed, but the road to the Dragovian realm is a long and tough one, and he did not survive. Xia then gave birth to the Hero, which she did not survive. The Hero was then exiled to the human world as he took the life of his mother, and Chen Mui disguised himself as a mouse to watch over him.
After Chen Mui has explained the Hero's heritage, he gives him the ring of the long lost Prince of Argonia. With this ring in hand, the player is able to unlock the true ending of the game after beating the final boss once more. In this ending, instead of kidnapping the Princess, the Hero simply shows the ring of his father to the King of Argonia. The King then acknowledges the Hero's royal blood, and lets him marry the Princess.
The Hero has a decent range of attack and healing spells to his arsenal, but is mostly a physical attacker. He is able to wield swords, spears, boomerangs, and attack with his bare fists. It is, however, generally agreed upon that his best choice of weapon is a sword, as his strongest weapon in the game (which is linked to his heritage) is a sword, and his strongest attack in the game is sword-based too.
His personal stat that no other character possesses is Courage, and will teach the hero a variety of spells and physical attacks. If either the Sword or Courage stat are maxed out, he learns Gigaslash. If both Sword and Courage are maxed out, which is possible to accomplish in a normal playthrough, Gigaslash changes into Gigagash, an even more powerful version of the attack.