Guardian Baou is the fifth and final Duelist of Death, as well as the only one to survive to see The Supreme King's downfall. He is also the only Duelist of Death that isn't a Spellcaster-Type apart from Demise, King of Armageddon, and the latter primarily acted through his components, Skilled Dark Magician and Skilled White Magician.
Baou later reappears when Jaden cannot bring himself to use Fusion Summoning cards. He decides to Duel Jaden in order to succeed the Supreme King, but is defeated.
Baou plays a Lockdown Deck. His Deck depends on using "Gravity Gain" in order to keep the opponent from attacking with monsters that are Level 4 or lower, the multiplication effect of "Fiend Slime Mold" provide Tributes, and attacks from "Twinheaded Beast" to destroy the limited monsters the opponent can Summon.