He is known for his work on film soundtracks, along with his unconventional approach to electronic music, including many live instruments not normally found on tracks within his genres.

At the age of 11, Varien began playing the guitar and attempting songwriting,[2] and he joined a number of bands experimenting with genres of rock, grindcore, metalcore, and jazz.

[3] He decided to focus on solo composition and began producing in 2009, with music in video games serving as his most longtime influence to date.

[2] He cites Shin Megami Tensei, Final Fantasy, and Metroid as his biggest influences when it comes to games, as well as the works of the Wachowskis.

His music was used in trailers and promotional media for 300: Rise of an Empire, Bones, The Purge: Anarchy, Face Off, America's Next Top Model, PlanetSide 2, and Monsters: Dark Continent.

Los Angeles-based singer Roniit's song "Runaway", produced by Varien, was used in multiple trailers and TV spots for the film The Loft.

In an interview with UKF, he elaborated on his songwriting process for the album, saying: "I make so many other types of music so I thought I’d sit down and write – no theme, no story.

"[2] The Ancient & Arcane met with critical acclaim upon release, with EDM website Dancing Astronaut calling it a "cinematic masterpiece", giving particular praise to "Ghost Spores" as "reinvigorat[ing] the soul with its harp-tinged melody and orchestral instruments that once again highlight Varien's idiosyncratic musicianship.

[11] In 2018, Kaelar announced via his YouTube channel that he would continue producing music under the Varien name, after his hiatus had allowed his to "take a deep breath from it all".

On October 2, 2018, Kaelar was quoted in RPGamer talking about his youth and which RPGs and video games inspired his career as a producer and composer.

"[13] Alex Fuller from RPGamer[14] commented on Varien's talent, "It's readily apparent how he has been able to utilize his gaming influences both in his electronic music and well as his soundtrack creations.

[16] | In an interview with EDM Joy, he described the EP as being the physical manifestation of his struggles during his hiatus, in contrast to the "fantastical" narrative of The Ancient & Arcane.

[17] On July 13, 2018, Kaelar is featured in an exclusive EDM Sauce interview talking about direct influences of his work, which includes Y2K Era, Fight Club, The Matrix, BBs forums for Final Fantasy, Rage Against the Machine, A Perfect Circle, Nine Inch Nails, KoRn, and "cool new electronic music like Drum n Bass, Trip Hop, etc," as what he declares as his "favorite era [of music]."

The EDM Sauce article features Varien's statement about his 2017 hiatus, declaring that he was being "ground down" by the industry and needed a break from it all.

In the Dancing Astronaut premiere and interview the author, Robyn Dexter, quoted Varien and the newly released EP as "consistently [surpassing] genre constructs and [proving himself] a true mastermind of the electronic music realm.

As one of Varien's most prominent features, EDM.com states that Kaelar is "on the same playing field," as Nine Inch Nails frontman Trent Reznor.

Kaelar states in the Raver Mag feature that he believes art, poetry, theory, philosophy combined with razor sharp logic, rationality, reasoning, and critical thinking can assist in practical ways of dealing with the world.

In the interview, he also states that if he had the choice to bring whoever he wanted to dinner dead or alive, he would choose Lana Wachowski, David Foster Wallace, Chuck Palahniuk, Marilyn Manson, and Brit Marling.