To side with Elder Elijah, my NRC reputation MUST be vilified ?

Can it be merciful thug, soft-hearted devil or even wild child?

By the way, I had blow BoS bunker, will this affect my choice to side with Elder Elijah?

I think it must be at least neutral or lower. I tried it with idolized and couldn't get it.

well as long as you talked with Veronica about Elijah before blowing up the BoS bunker I think you should be fine

What happens if you side with him?

The game ends and you get an ending slide describing what happens to the Sierra Madre and the Mojave. After that, you'll return to (I think) your last save and you're able to finish the DLC the normal way, allowing you to go back to the Mojave.

WTF!?

I cannot proceed after that ending? So that is an ending which will never happen if I want to continue my game, similar to the ending which I am trap and die?

I want to conquer the world... :sadvaultboy:

What can't he just let me leave after I said I want to side with him?

Yeah it's pretty much like the ending where you're trapped in the vault. The ending is so drastically different from any other it would be impossible to fit into the main questline.

Ya, but what does it say in the slide.

You tube is your friend
http://www.youtube.com/watch?v=O1Gqv1dbuTw&feature=related