First off, I wanted to let you know that this a very great profound piece that truly evokes deep emotions from those who listen to it! On a second note, it is very popular as just about every Under Judgement animation I have watched lately has this piece included. Congratulations on not just beautiful music, but a hit as well!
The reason why you hear this in a couple of animations is because it was for the NATA Novice round, where animators had to pick one of the 4 songs and draw an animation from it :)
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