Thread:Matsczon/@comment-25354565-20200210184110/@comment-4511886-20200210220414

The nestling isn't considered a merchant because it doesn't use a trade window that lets you exchange souls for items. So the category is based on the mechanic rather than the literal definition of a merchant.

To give another example of this: Ludleth and Straid both make the weapons they offer, but aren't categorized as blacksmiths. This is because they don't provide the services you'd expect from a blacksmith NPC, such as repairing and upgrading weapons.

Hopefully that clarifies it.