Strategy hint needed

[Zingo]

Could someone give me a strategy hint on how to proceed?

I have just cleared the eleven quest to free the sole of the eleven princess and given the option to enter the locket gate the "eleven river land". But is here where I'm a little puzzled on how to proceed. I can see in many threads that some of you strongly recommend to clear the demonis land in dwarf lands.

Why should the demonis land be cleared before entering the locked gate?

Is there more areas that should be cleared before I enter the locked gate? For example the two land that can be reached by the book of death.

Further more, where can I recruit eleven hunters? I can not find them any where in the eleven lands (not a single enemy left to kill and all areas checked, including the castle behind the green portal)