I have run into a few comments across the net about the legality of Nevergrind due to having a lot of similar concepts as EverQuest and Diablo 2. When I decided to monetize, I did my homework and changed the game as much as I thought necessary. Even using stuff like the Kunark titles is fair play as far as I can tell. Check out these links on the topic. Interesting reading if you get excited about this sort of thing:

• Copyright Registration of Games
• Why Words With Friends Hasn't Been Sued by Hasbro
• Copyright law: Transformativeness and derivative works

before Lake of Ill Omen existed in the world of Norrath, it was the name of a lake in the dark world in The Legend of Zelda: A Link to the Past on SNES

and many names of NPCs in EverQuest were taken from outside sources. in particular a lot of the names were taken from the A Song of Ice and Fire book series (aka Game of Thrones)

would be pretty hypocritical for the EQ team to take offense to NG borrowing some names and concepts.

Everquest was derivative of DIKU Mud. At least according to Bernie Yee.