well this isn't a question, so I don't know how to answer it, but can tell you some info on it.
It was composed by Nick Pheonix, originally on the album "Dreams & Imaginations." It is available for public purchase on the album "Archangel" on iTunes or Amazon. It was uploaded to october on 10/9/11 and as of 7/20/14, has over 90.3k views.
big meme
I think with my knowledge, the closest I can think of right now to "Mercy in Darkness" would have to be Caradhras. It's got the similar type of calm and sining introduction. It gets a little bit harder at the end, but sill a great song.
The name of the haunting song in the Twilight trailer is "Mercy in Darkness" by Two Steps from Hell, from their collection "Dreams and Imaginations". The music from Two Steps from Hell is not available commercially as they are a studio that produces original scores for theatrical trailers and marketing. http://www.twostepsfromhell.com/twilight.php -Travis Hiland
Nemesis - Two Steps From Hell album - was created in 2007.
Invincible - Two Steps From Hell album - was created in 2010-05.
two steps from hell
"Down with the Enterprise" - Two Steps from Hell "Freedom Fighters" - Two Steps from Hell "War Begins" from Children of dune - Brian Tyler
"Master of Shadows" by Two steps from Hell
The first 1 minute 53 seconds is a song called Love and Loss, by Two Steps from Hell. The second song is called Infinite Legends, also by Two Steps from Hell.
The song in the launch trailer of Mass Effect 2 is calledTwo Steps From Hell-Heart Of Courage
Two Steps From Hell- Heart of Courage
No