GM, chill, you're being mean :p
Diminish, I actually like this dude (although I don't like his name), maybe I understand where you were going with him better. He isn't a major character that's really related to the plot, and his only mechanic is to better implement a collecting stuff quest. These are really common things in Zelda games, I feel like he fits really well. He also represents 1) how the rich are generally greedy, fits with our theme, and 2) how the poor are desperate, also fits with our theme. But also gives a slight nod to the sentiment of hey, just because the poor are poor doesn't mean that stealing is moral.
I like how this guy fits into neither category, but does relate directly to Link, as an adventurer. He isn't in it for the money, like the rich and poor are.
But yeah, all this stuff is character NPC stuff, so I guess not the right board, but we've had a few topics where (for example), the boss topic is created and mentions an enemy that doesn't exist yet, like wolfos.
So anyway, about the side quest, I like it. Secret seashells hold about as much significance and medallions from OoT, why do they need to be seashells? We already have a graphic from MC :p
I also like how he built vaults in the sewers, that's kinda cool.
My only problems are... A heart piece for one coin, and.... I don't nderstand the vaults. Are they mini dungeons, or just rooms full of treasure. Also, Link is collecting the coins, has the guy lost them? Or is Link just finding new ones? I think it'd be cool if there were a finite number of the coins, all taken from an ancient ruin or something, and some HAD been stolen from the guy, and Link returns them to his collection.
So I'm all for implementing this, the seashells were vague and not fleshed out, they were kind of just a place holder item. And now, something better and more interesting has come along.