A question about the usage of ため and spacing


上下のフロアを繋ぐ階段は各層にひとつのみ、その全てが怪物のうろつく危険な迷宮区画に存在する`ため`発見も踏破も困難だが、一度誰かが突破して上層の都市に辿り着けばそこと下層の各都市の≪転移門≫が連結される`ため`誰もが自由に移動できるようになる。

There were 2 things I didn't get in this sentence (or maybe a paragraph...?):

  1. What is the usage of ため in the two appearances of it in the text? (Marked)  
I could tell that it's not the normal usage of ため+に・の and it doesn't makes
sense to me as well.

  2. How can this `怪物のうろつく危険な迷宮区画` be translated (literally)? I don't get the spacing in this part... According to the dictionary, the na-adj meaning of 危険 is "danger, peril, hazard"... What I don't get is how exactly "danger" is an adjective? There is another option of "dangerous" in the dictionary, but it wasn't marked as a `na-adj` meaning. Ignoring the adjective comment I made above, I'd translate it as "A maze area in which there is a danger of roaming monsters" or something like that - but I wanna know why if possible :-)

Thank you in advance!  
The sentence above was taken from the novel "Sword Art Online 1"!




  1. ため can be used to indicate reason/cause. It is always best to check [a Japanese dictionary](http://dictionary.goo.ne.jp/leaf/jn2/139016/m0u/) when you can.

  2. The sentence should be parsed as (怪物のうろつく) 危険な迷宮区画, i.e. the sentence 怪物がうろつく modifies (as relative clause) 危険な迷宮区画 (keyword ga/no conversion).




  1. ため can be used to indicate reason/cause. It is always best to check [a Japanese dictionary](http://dictionary.goo.ne.jp/leaf/jn2/139016/m0u/) when you can.

  2. The sentence should be parsed as (怪物のうろつく) 危険な迷宮区画, i.e. the sentence 怪物がうろつく modifies (as relative clause) 危険な迷宮区画 (keyword ga/no conversion).

