RPG Insanity

I have completed the game story except the boss rush and the some of the encyclopedia. I have seen the info where the few final monster are at dusk ruins. However, I do not know how to gain access to dusk ruins. Does it have something to do with dawn ruins? Please help, thank you very much.

If I can remember, if you go through the Verde forest there is a rock that you break toward the end.  Breaking that and following the path opens up Dusk Ruins.