Babis "Bob" Katsionis (Greek: Μπάμπης Κατσιώνης; born February 17, 1977, in Athens, Greece) is a Greek guitarist and keyboardist and the lead guitarist and keyboard player for the heavy metal/power metal bands Stray Gods, Warrior Path, Outloud, and Serious Black; he was part of Firewind, before leaving in 2020 for personal reasons.

[1] He is the only musician to ever win the same category "Best Keyboardist" in Greek Metal Hammer's Annual Readers' Polls for 5 years in a row (2006–2011).

For instance, when Firewind play live, he performs in a dual role as keyboard player or rhythm guitarist (or both), depending on the song.

[5] and has also joined his idol's Timo Tolkki (ex-Stratovarius) band Revolution Renaissance for the recording of their album "Trinity" without making any live appearances.

After Bob filled in live for Roland Grapow on their tour with Hammerfall (January–February 2015), Serious Black announced him as a full-time member in February 2015.