[6][7][8][9][10] Some songs also have electronic shades, djent transitions and folk metal melodies derived from Middle Eastern, Chinese and Celtic traditions.

[11] Epica is also known for the attention to the vocal lines that, in contrast to the heavy context, weave very catchy, easy to hold, sophisticated and emotional melodies.

They primarily write their own lyrics, which often deal with philosophical, psychological, spiritual, moral, scientific, environmental, socio-political, global and topical and personal themes.

[18] Their seventh album, The Holographic Principle, was released in September 2016 to continued international success, equalling the peak chart position set by its predecessor in the Netherlands.

The band's line-up was completed by guitarist Ad Sluijter, drummer Jeroen Simons, bassist Yves Huts, and keyboard player Coen Janssen.

Epica then assembled a choir (made up of two men and four women) and a string orchestra (three violins, two violas, two cellos and an upright bass) to play along with them.

Consign to Oblivion was composed with film scores as a basis, with Hans Zimmer and Danny Elfman cited as major inspirations.

Epica also joined Kamelot as a support band on parts of their tour for promotion of The Black Halo album, to which Simons had contributed her vocals on the track "The Haunting (Somewhere in Time)".

In December, Ariën van Weesenbeek from God Dethroned was announced via Epica's official website as the guest drummer for their new album, but not as a permanent band member.

[citation needed] In September 2007, Epica headlined their first tour through North America and released their third album, The Divine Conspiracy, this time on a new label, Nuclear Blast.

The band toured North America again in April 2008 with Into Eternity and Symphony X, this time with Amanda Somerville because Simone had contracted a staph infection (MRSA).

The concept that guides the songs is that God created many different religions for humanity to figure out and overcome them so as to discover that, in nature and essence, they were all in fact the same one (hence the name, "The Divine Conspiracy").

He left a message on his Myspace page with his reasoning for leaving the band, which included frustration over being unable to enjoy composing music because of deadlines.

It included a 40-piece orchestra and a 30-piece choir, and the setlist contained not only the band's songs but also covers of classical pieces of Antonio Vivaldi, Antonín Dvořák, Giuseppe Verdi, Edvard Grieg, and of soundtracks of the movies Star Wars, Spider-Man and Pirates of the Caribbean.

On December 1, the band announced that the name of the album would be Requiem for the Indifferent, and would be inspired by such factors as the enormous tension between different religions and cultures, wars, natural disasters and the financial crisis.

AllMusic stated that the album "is a typically elaborate and ambitious affair, incorporating copious amounts of choral work and classical arrangements into the band's neatly established blend of goth, progressive, power, and symphonic metal.

"[45] Natalie Zed of About.com staff considered Requiem for the Indifferent "a transitional album for the band", which tries to expand their musical range experimenting with "weird" riffing and new combination of vocals, while "losing none of the richness that has gained them fans.

"[46] On 16 September 2012, the band made a guest appearance on the Dutch TV show Niks te gek (translation: "Nothing [is] too crazy"), where mentally disabled people (18 years or older) can get their wishes granted.

[48] The concert consisted of a 70-piece orchestra, special effects, acrobats, guest vocalist Floor Jansen (Nightwish) and former band members Ad Sluijter, Yves Huts and Jeroen Simons.

[52] Later that same month the band unveiled the album's cover art, which was created by longtime collaborator Stefan Heilemann to accompany the ideas behind the lyrics.

[17] The band stated that, "Where Retrospect reflected on the first decade of our career, we'd like to think The Quantum Enigma marks the beginning of a new era, where Epica sounds heavy, modern and without compromises!

[58] The band returned to the stage after almost a year on 30 April 2013, in Tilburg in their home country, The Netherlands, which marked the album release show.

Epica announced Epic Metal Fest on 3 June 2015 on their official website and revealed that they would be joined at the festival by bands DragonForce, Eluveitie, Fear Factory, Moonspell, Delain and Periphery.

[65] The band announced on 17 July 2019 that a Gold Edition of their album Design Your Universe would come out on 4 October 2019 in support of its tenth anniversary, along with a tour.

[73] Nuclear Blast later announced on 7 October 2020 the title for the band's eighth studio album, Omega, along with a release date of 26 February 2021.

[77] In support of the album, the band performed a livestream event titled Omega Alive, which took place on 12 June 2021[78][79] and was released on several audio and video formats on 3 December 2021.

In May 2023, Epica was chosen to open for Metallica with Ice Nine Kills for a short run of shows in Paris and Hamburg on their M72 World Tour, replacing Five Finger Death Punch, who had cancelled their appearances due to health issues.

[92][98] Epica uses a "trademark of many symphonic and gothic metal bands" in contrasting "two extremes, death grunts and brutality on one side, airy female melodiousness on the other.

"[92] Eduardo Rivadavia of AllMusic notes that the band's "attraction ultimately hinges on exploring the sonic contrasts of light and dark; the punishing intensity of those elephantine guitar riffs and hyperactive drumming cast against the soaring, layered sweetness of the orchestrated strings and keyboards.

"[98] The group is also known to employ human choirs and orchestras[106] with additional embellishments such as spoken word recitals and lyrics in Latin and Arabic.