The final regular job, Hero, is a bit trickier to unlock. First, players need to have mastered the Ninja, Spell-sword and Acrobat classes. 
Then they also need to obtain something called a Hero License from the Castle in the Clouds. This is no easy task, as players need to find the entrance to this hidden area and then use a special item to fly up there -- only that special item requires the player to defeat a specific opponent on a random battle space. Given that this is the most powerful regular class in the game, and has abilities that can either allow players to cast magic and use items in the same turn or force non-boss enemies to immediately give up, it's easy to see why there's so much work involved in acquiring the Hero class.
However, there is one more class that hasn't been mentioned...
It is the Darkling class, and unlike every other class in the game, it is not permanent. It can only be unlocked by a last-place player who is hearing "the whispers of dark revenge" (i.e. has a shadow bat-like creature floating over his or her head). Once a player reaches this status, he or she can either travel to the Dark Space on the board or use a Contract item to warp there directly. There, the player has the option of surrendering all of their items, money and towns in order to become a super-powerful Darkling for 14 days.
The Darkling is immensely powerful and has the strongest battle skills in the game. Opponents cannot retreat from battle against a Darkling, and assuming the Darkling wins (which it most likely will), they can lose their equipment, items, money or towns. Also, before every turn, Darklings spin a wheel that grants them Dark Points which when accumulated can be used to set traps, close shops and banking spaces, or even summon monsters to every available town on the world map.
Finally, we'll conclude this guide by showing you a way to trigger a slightly different, alternate ending to Dokapon Kingdom's story mode. When the game begins, the king promises his daughter's hand in marriage to whoever wins and saves the kingdom, and normally that's exactly what happens once the game is over.
However, if the individual who wins is playing as a girl, things play out slightly differently. I don't want to spoil anything for you, but do know that it results in a different and longer ending and involves some creepy scenes. The king puts on a wedding dress. There, I said it. If you're interested in knowing more, make sure you go through the game as a female character so you can witness all the zaniness that ensues. Good luck and happy gaming!