The 2nd of the two albums, Ultra, was announced on November 11th, 2015, by its first single, Nastalo Bo and was released almost exactly 6 months after its predecessor, Infra. Just like Infra, Ultra was also entirely recorded in the band's own studio, Studio 13 (with the exception of Urban's vocals on Strele v Maju), and was produced by Dejan Radičević. Ultra also brings the band's second collaboration with DJ Umek (In Levitation) and introduced their first time collaboration with croatian musician, Damir Urban (Strele v Maju). The later was also treated as a video, which was released on February 22nd, 2016. The bonus song, Road, was entirely written and performed by Siddharta's long-time crew.
On February 15, 2016, the band performed on national television, most of the songs performed were taken from Infra and Ultra and Damir Urban joined them on stage as a guest on Strele v Maju.
- Nastalo BoDirected by Matej Grginič
- Strele v MajuDirected by Matej Grginič