Is the Seller Serious?
A legendary skill is something not anyone could pick up. Only a handful of players could get one as even NPCs that are rated legendary could use or teach a player a skill like that. Even if it is an epic skill now, just the assurance that the skill book can evolve into a legendary one would increase its price astronomically.
The first thing that popped in the heads of those that are in the auction is "who would sell a potential legendary skill?". Nevertheless, why would they care as the only thing important now is they people in this room had a chance to get a legendary skill. They eagerly waited for the conditions for the trade.
"The seller of the skill book would like to exchange a legendary weapon for the epic skill book. We will show you the details of the book that a highest rank appraiser of the merchant guild personally inspected." Mei stated as she gestured at the monitor.
Item: Abyss Dragon Breath (Degraded) Skillbook