Shin Megami Tensei: Raidou Kuzunoha Vs the Soulless Army/King Abaddon Akarana Corridor (Extended) 

I love this theme, too. I've finished DS2 today, and the first thing I wanted to do was to listen to that theme again. It played in Ishigami, but I knew I heard that before, and guessed right the Akarana Corridor theme. BUT that's not exactly why I like it... It's because, it remembers me so much the Digital Devil Saga atmosphere... I think there is a very similar theme in DDS, similar to 1:13 . I'll try to find it out, and if I'm right, I edit here.

Travelling the Akashac records in the flesh - That's so teepin' wild!

thank you!

Cool!