The Merchant is the only other human character in the game. Here is a list of what he says on each level.
Level 1 - Welcome, friend, to my shop! Feel free to browse my inventory, or even sell some of your own items you don't need!
Level 9 - Ah...congratulations on making it this far! Was it difficult? I dearly hope not, for the dungeon only becomes more perilous from here! Can I get you any supplies?
Level 19 - We meet again! Did you know that each time you restart a quest, you start at the next to last shop you visited? That's right, if this shop on floor 19 is the deepest you've been, you'll start at the shop on floor 9 next time!
Level 29 - I see you know how to fight! I must warn you...the next series of floors become quite dangerous. I recommend you go well-prepared... Are you remembering to stock up on healing potions?
Level 39 - Hahaha... you must think you're strong! I am afraid you may be overestimating yourself...
Level 49 - Well, you've made it halfway. From the looks of you, I don't see yourself making it much further, however.
Level 59 - Interesting... have you had much trouble thus far? Can I assist you with some supplies?
Level 69 - Heh heh! How are you enjoying these catacombs? You're getting very close, but you still have thirty floors left!
Level 79 - So... I will admit it. I may have underestimated you... a little. Might I suggest you be well prepared for these final twenty floors...
Level 89 - ... Hmm. You must have gotten lucky to have made it this far.
Level 99 - ...
Level 100 - ... What? You? How can you have made it all the way here? GAH!!!
Level 100- I'm tired of this... I challenge you to come and fight ME!
Level 100- ... This... can't be...
The Merchant is a immortal/mortal being that will lure anyone into his cave to buy his wares that he collects from the dead Adventurers that seek a fortune. .