At the sake of sounding like a nub...SPOILERS INSIDE

[Darius]

I unlocked the Dragons Den. I know this because I got the messege "Ill be waiting" or whatever it says. Everywhere Ive looked says that the Den is located in the Northwest section of the map. Ive gone over the entire northwest section and I havent found it. What gives?

[Bunny]

From what I can gather, it is on a small island located North of the Coliseum. I haven't unlocked it quite yet, so I don't know for sure what the exact location is. Just keep flying around up there until you spot an island with only a tree on it.

[Darius]

Ah Ive seen alot of islands with a single tree. Guess ill just land on them all

[Fatal Impurity]

Maybe you've seen the same island loads of times by going around in circles?

[Darius]

I found it. I was flying around the entire area looking for an actual cave entrance. Didnt know I had to just land on a specific island. Anyways, Im almost done with the DD now.