Ok, I have done a few side quest and have completed the Main Quest "The Prophecy".
Couple of questions please.

Can I get into the Dark Tower now and where is it located?

Do the 4 allies I picked in The Prophecy go and stay in the Dark Tower, or do I have to travel to where I found them to use them?

Thanks in advance

I've always been crazy, but it keeps me from going insane.