Wow. There is lots to know. And, apparently the tip of the iceberg. I had to do plenty of googling as it is. Starting with DOTA — Defense of the Ancients :)
It is interesting to see the characters, which you plan for next installment. I rather enjoyed browsing through them, an example: http://www.dota2.com/hero/Queen_of_Pain/
Clearly the roles and identities are very complex as well as interactions.
As I understand it. the themes of characters/roles, place, and strategy are very strong. Also, items are of relevance (http://www.dota2.com/items/). I really enjoy the naming creativity in these spaces. Then, as you point out, comes the emergent terms and expressions.