[lucagalbu]

Hi! I'm trying to translate this rules taken from the anime Death Note:
人間は、いつか必ず死ぬ。死んだ後にいくところは、無 である。
I know the translation is: "All humans, without exception, eventually die. After they die, the place they go is the nothingness.

Well.. my problem is that I can't understand it very well:
1)If "death" is "死", then what is "死んだ"? Maybe だ is the plain form of "to be"?

2)いくとこる: I think this is the verb 行く, but what declination is it?

3)無である: de aru: what is it? Is it a declination of です?