As of January 27, 2017- it is Left Behind by DAGames.

I am really iffy on this YouTube artist, my brother likes his music more than I do, but I gotta say, this one song is pretty good. His voice is perfect for FNaF related songs (this one is part 5), he can switch from a calm evil, to an aggravated evil exclamation, to a very powerful and angry yell. In addition, he can do the typical heavy metal growl to add a much darker theme to this techno-based song.

But there's a part in the song- towards the end, where I just get goosebumps, because the power of this guy's vocal cords is super prominent! Like, I can feel the passion and anger in his lyrics! This dude deserves to be in a Nightmare Before Christmas 2 (I wish) Soundtrack!

Attached is le song.