From HoNwiki

How do I log in?

Use the Login link at the top right corner of the page. Enter the username and password used to log into HoN.

How do I create a new account?

HoNWiki can only be accessed by verified accounts. If you wish to use HoNWiki you must first log in with your Heroes of Newerth account.

I can't log in! Help!

Usernames containing an underscore ( _ ) cannot log into HoNWiki. Please remain patient as we will fix this as soon as possible.

If you are still unable to log into HoNWiki, then please contact Customer Support[1].