
Archmage Variel |

I love Black Fang's dungeon. The classical feel of the dungeon and intuitive rules of the Beginner Box is a great way to introduce anyone to tabletop roleplaying, but the one negative aspect of that entire dungeon has always been Black Fang himself.
After sludging through an entire dungeon, first time gamers saw the dragon and wanted nothing more than to call themselves a dragon slayer. But as low level player's, black fang isn't supposed to be defeated so easily. You want to give them the feel that this is a powerful beast that may have ended you were it cournered. But if they aren't close enough to death's door and the enemy he flies away, I often get players who feel cheated, not yet fully understanding that this is a narrative game.
That isn't in my opinion a particularly fun introduction to this game. So, instead I propose to you the Injured Wyvern, a scaled down version of the original Pathfinder Wyvern suitable for dragonslaying. The injured wyvern fled it's home in Wyvern Mountains after a territory battle which it lost. It fled to the hills near sandpoint, where it hunted cattle from the surrounding farms.
Sandpoint has had enough, and your adventurers are the ones who have decided to take up the bounty of clearing out a dungeon believed to be the home of whatever deadly creature has been stalking Sandpoint's farmlands.

Archmage Variel |

Looks like a pretty reasonable change. My PCs personally wouldn't really feel finishing off a wounded creature warrants the title "dragon slayer", but that would be an individual preference.
I designed this with the premise that I want to give new players a boss monster who feels iconic and satisfying to fight, while giving them the realization after further play that such a fight was nothing compared to the colossal threats which live in the world. I didn't want them to get the permanent impression that they were dragon slayers, but I wanted new players to get the impression that they had slayed something akin to what any commoner (or someone who's never played a tabletop rpg before) would think a dragon is like.