Babis "Bob" Katsionis (Greek: Μπάμπης Κατσιώνης; born February 17, 1977 in Athens, Greece) is the rhythm guitarist and keyboard player for the heavy metal/power metal bands Firewind, Revolution Renaissance, Outloud, and Serious Black. He is considered to be Greece's most successful rock/metal keyboard player, being 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).