Decon's commentary:

I've said it before, and I'll say it again; more games need rotterdam techno/gabber/speedcore etc. final boss/true final boss themes. It always absolutely fucking slams when they do. Which is funny, because my first instinct with this song was to not do that. I was actually gonna go for a more typical dark rave type piece in lieu of ANOTHER RAVE ORDER, and an early sketch was put together in that style, but oh my god it did not work at all. Stumped, I changed tracks, thinking “well I guess I can just do rotterdam for Pied again”; that started off way more promising, but now I was struggling to come up with chords for it. Genuinely, I cannot remember how many sequences I tried out over that bassline in the intro to see what would fit. Borrowing the chords from BM2's intro theme/stage 8 tune, adjusted to fit the key, was something of a move of desperation on my part and I openly admit that. It paid off, though- once that chord sequence was in there, the track began to flow and come together much more cleanly (up to and including allowing me to figure out chord sequences for other portions of the track- go figure). It also lead to a weird bit of extra additional foreshadowing about Pied being the Man Behind The Man of BM2's plot (something which was supposed to be blatantly obvious and a cheesy twist, inspired by the early Mega Man titles introducing new threats only to reveal it was Dr. Wily pulling the strings all along the whole time!!! for like, three games in a row): I'd deliberately incorporated that chord sequence from the intro into the stage 8 tune to closely associate it with Kain- a sort of additional motif in addition to the ones from Heartless Hatred- but now, both of those songs are hinting at Pied's being the mastermind (one of which doing so from the word “go”). It's not even remotely clever, but it's neat!
I'm extremely happy with the track on it's own merits, though; when it began to take shape, I felt that it did better justice to what I was going for with Pied's theme for the first Battlemania. The tempo is slightly slower, sure, but there's a bit more compositional depth and a little more meat to the arrangement in places that make it resonate more emotionally. Particularly with the more personal stakes the Kingslayers have in taking Pied down vs. The Brave Hearts in BM1, who were pretty much solely fighting for the fate of the world and the fallen players more generally.