He has recently produced some of the band's albums and contributed as session keyboardist.

[2] Sakis has also provided guest vocals and guitars for a number of bands, for example providing guest backing vocals on the track Mocking Modesty on the Nightrage album Wearing a Martyr's Crown and additional vocals on Spanish North of South's single "Just Fourteen Seconds", taken from their The Tides in Our Veins album.

[3] He also played guitar in a black/death metal band Thou Art Lord,[4] which features members from several other prominent Greek extreme metal groups, such as Necromantia and Septic Flesh.

He currently has a signature V-Shaped guitar with the Greek letters ΧΞΣ inlaid in the fretboard.

In 2018, Tolis announced he was co-authoring a book titled Non Serviam: The Official Story Of Rotting Christ with Dayal Patterson.