I/JG54_SerpentBlade's Requiem artist?

[Strewth]

So....................
Yes, I have loved this clip ever since it came out and still watch and listen to it regularly.
Even though the graphics were dumbed down for file compression, the images tell a great but sombre tale.

Something I have searched for without success over the years, is the origin and artist of that particular version of "Ave' Maria".
Personally I think it is a great version with a lot of feeling.

Would anyone know and be able to share the artist / original version?

Thank you in advance.
Cheers.