ok a little spoiler here for those that don't know. Omega challenges the warrior of light in FFXIV with several test with the hopes of figuring out how it is possible the player (the warrior of light) surpasses their mortal limits, and in return Omega will assimilate that data unto its own.
The final test was Omega itself, and after defeating its base form he took on a more human like figure after studying the warrior of light.
In my opinion the second BGM is a lot better than the first one.
BGM / Omega: Alphascape V3.0 Theme
BGM / Omega: Alphascape V4.0 Theme OST