I think it's 5-2... it's been a while. Whichever mission Shadow Lord is summoned:
Based on the Youtube comments, I too think this is no amateur work (it sounds too professional), and given the Twitter channel it came from, it seems like a collaboration of some sort, it looks semi official.
If I'm right, is Shadow Lord: https://en.wikipedia.org/wiki/Norio_Wakamoto ?
Or basically, Perfect Cell! :D -- there's no credits. It's just a hunch.