C Tier

The class ranked here isn’t bad, but pales in comparison to any of the options above.
Merchant
In a weird way, the Merchant both is and is not the worst class in Dragon Quest III HD-2D. It is usable, as it can inflict respectable damage and equip some strong weapons. The Merchant also can find extra gold after battles, which can be helpful early on while money is relatively scarce. You can even use the “Show” command with a Merchant in the party, which gives you a full and fun description of every item in the game. It’s a really neat touch!
The Merchant’s problem is that it offers almost no long-term benefits to your party. Sure, the Show command can let you know if an item is cursed, but that’s usually specified in an item’s description already. The skill Service Call technically lets you use Inns on-demand, but it doesn’t work in the dungeons where you’d need it the most. It does learn the powerful attack Call to Arms, but this is a later-game move and is functionally identical to the Monster Tamer’s Monster Pile-On, which is overall cheaper to use.
Merchants aren’t bad, and they are fun to use. But of all the classes in Dragon Quest III HD-2D, this is the easiest to skip.