The backstory of the epic 'Game of Thrones' finale song fans still can't stop streaming

WARNING: Spoilers ahead for "Game of Thrones" season six.

The literally explosive "Game of Thrones" season six finale was shocking to fans on many levels. Not only did Cersei successfully blow up the Sept of Baelor and kill hundreds of people (including Margaery, Loras, Mace Tyrell, and her uncle Kevan Lannister), but the way the scene played out completely surprised viewers.

The finale opened with a soft piano music, eventually building up to unsettling cello solos with loud organs and a spooky children's chorus. This song, titled "Light of the Seven," was written by the composer who has been with "Game of Thrones" since season one: Ramin Djawadi.

Tech Insider spoke with Djawadi about the creation of this unusual (and extremely popular) "Game of Thrones" track.

"What's so cool about 'Light of the Seven' - and what I love about 'Game of Thrones' - is you never know what's going to happen," Djawadi says to Tech Insider over the phone. "You never know who's going to die, you never know who's going to turn on who."

The piano played a huge role in subverting fan expectations for Cersei's wildfire explosion. "It's always interesting to go in different directions with instrumentation, so the piano was such a surprise to people because it's just not in the language of the score at all," Djawadi explains. "We've never used piano before."

The piano may have sounded anachronistic to some viewers, but Djawadi thrives in the made-up universe of Westeros and Essos.

"What's cool about 'Game of Thrones' is that it's a fantasy show and anything goes," he says. "So if we feel [a song] fits creatively, we can make it work. I've used all kinds of instruments [that don't] have to be period specific. That's why the piano really took people by surprise, but I'm happy that people actually loved it and that it was a pleasant surprise."

The fandom has certainly reacted with overwhelming positivity. As of the time this article was published, Djawadi's "Light of the Seven" track was the number one trending song on Spotify's "Global Viral 50" chart.

"I love that," Djawadi says upon hearing the Spotify news. "That's incredible. That doesn't happen very often with a 10 minute piece of music like that."

We asked how the initial idea for "Light of the Seven" came about, given it was such a big departure from the usual "Game of Thrones" music. Part of the process was having showrunners David Benioff and D.B. Weiss, along with director Miguel Sapochnik, talk through the Sept of Baelor scene in advance with Djawadi.

"We discussed this very early on, because it's such a significant scene," Djawadi says. "There's not a lot of dialogue and it's a very long scene. [Sapochnik brought the piano up] and we all discussed it. We went back and forth and experimented quite a bit and then we ended up just going for it. I'm so happy we did."

Another important point Benioff and Weiss made was that the music played during the opening scene couldn't have any ties to Cersei's previous themes. Most fans would recognize the Lannister theme, "Rains of Castamere," and suspect she was up to something.

"They said 'Look we would love this to be a completely new piece of music [...] we don't want to tip it in any direction,'" Djawadi recounts. "Then we came up with the idea of using organ for her because we used it for the [Walk of Atonement], so organ was already in the score's language. The organ also made sense because of the religious aspect, so it was great instrument to add. The organ is so powerful - it just has this great build to it."

Later, during Cersei's ominous coronation scene, Djawadi was able to blend the "Rains of Castamere" into "Light of the Seven." The new song, which can be heard on the soundtrack as well, was named "Hear Me Roar" - the official words of House Lannister. "Now that [the audience] all knew what she had done, it was great to reprise that new music and implement the Lannister theme on top," Djawadi says. "That was really fun to do."

With season six behind him, Djawadi is eager for more "Game of Thrones" footage to be sent his way. "I have no idea what's next, so I'm excited, too," Djawadi says.