Onur, Erce and Murat came together to establish their own music studio to provide professional production services. In 2016, they decided to make their own music and founded RONNIN. After releasing two singles independently in the same year with vocalist Enver Yılmaz, the band started working on their debut album. Before Ayberk Zaknafein joined as a vocalist in 2019, they worked with Soilwork's vocalist Björn "Speed" Strid on the song "Heretic God". After the line-up was completed, the band produced their debut album throughout 2019-2020. In this album the band also worked with Pentagram/Mezarkabul's legendary vocalist ''Murat İlkan'' on the song ''Greed of Humanity''. 

The album “Repression” talks about greed and ambition of human kind and how the dogmas corrupt it. 8 tracks in the album address these issues. The album production was made by the band in their own studio, "Studio Ayı" in Istanbul. Mix was done by Onur and Erce, and mastering was done by Jens Bogren at Fascination Street Studios in Sweden.

While Ronnin combines Death metal and Metalcore, they also includes many progressive metal elements in their music. In addition, the two instrumental tracks 'Zarathustra' and 'Lagertha' on the album support this combined style. Vocals: Ayberk Zaknafein Guitars: Onur Narin Guitars: Emir Saygan Bass: Murat Dinc Drums: Erce Arslan