A long shot, I know, but after being awestruck for years with the opening "song" from TNT's 1988 album "Intuition" (A Nation Free http://www.youtube.com/watch?v=xgHzPcag6os ) I now try to find complete songs which have that majestic feeling that, in my mind, is a bit dark at the same time. Any sub-genre is welcomed, and so is any band for that matter. I also wish there to be either keyboards, church organs, whatever, or even orchestras. Only demand is that it doesen't sound too childish and/or dungeons and dragons-nerdy.

Thanks.

Blood Ceremony's "Master of Confusion" opens with a really chilling bit of organ

Here's some of my epic metal favorites


Atlantean kodex : pilgrim, very good live version here
Therion : Adulruna Rediviva
Nightwish with Floor Jansen : Ghost love score Live

While Heaven Wept - epic/symphonic doom. I can't read your mind but I think this is exactly what this thread needs

SIG:AR:TYR - epic viking metal that's generally pretty somber. think Bathory/Falkenbach/Agalloch. not as sugary/powery as previous suggestions

HMKids should work great for you. They match the atmosphere of Warhammer 40k, their lyrical subject of choice.
Tzeentch
http://www.youtube.com/watch?v=Z_zSVBMrEE4
Adeptus Mechanicus
http://www.youtube.com/watch?v=-ecvLRxb3MU
Nurg-let
http://www.youtube.com/watch?v=q-S5SR63tIE
Chaos Temptation
http://www.youtube.com/watch?v=rqsBgFczAF0
Eldar
http://www.youtube.com/watch?v=gSx3w2JhYtA
Cadia
http://www.youtube.com/watch?v=Gzf3vaAcOPA
Prospero Burns
http://www.youtube.com/watch?v=5lbYb9OOh_I

I think you get the picture.

Here's a few songs that i would constantly use "majestic", "epic"

Thyrfing - Griftefrid
http://www.youtube.com/watch?v=sUreZwGqBr8

Sear Bliss - Birth Eternity
http://www.youtube.com/watch?v=w-B0Wx9JndU

Anything from Summoning
http://www.youtube.com/watch?v=rosj5h3jI2U

Septicflesh - Virtues of the Beast
http://www.youtube.com/watch?v=BJAJqNwlPUw

I don't know if this is dark enough for you, but it is epic, majestic, and contains lots of keyboards, here is Lordian Guard. Warning: Lyrics include Christian themes.

Lordian Guard - Sinners in the Hands of an Angry God
Lordian Guard - War in Heaven
Lordian Guard - Revelation XIX

Before Lordian Guard there was Lordian Winds, some of which songs were re-worked for Lordian Guard, and for the most part weren't metal. However, the following song I would probably call non-ballad acoustic metal. Meaning, it's on an acoustic guitar, but it could just as easily be on an electric guitar and be a metal song. Less keyboards, though there are some, and the song is darker, and the lyrics don't deal with Christianity.

Lordian Winds - Dark Civilization