It is ridiculously hard. But I chalk a lot of that up to how none of the monster stats (class, type, etc) make any sense. That is why I was wishing someone had put together some kind of guide. I am struggling to understand why certain monsters get grouped with other, what is most effective against what, what monsters are best for invading what areas. It really feels like there is no actual methodology behind the combat and that really sucks because invading is probably the best part of the game.