Zedonius is one of the Four Greater Fiends of Vazdah and a villain from Ninja Gaiden 2.
Eons in the past, Zedonius and his fellow Greater Fiends were placed in a deep sleep by the Dragons. But after several millennia, they found freedom at the hands of Dagra Dai and Zedonius attacked Russia, the former military super power. The army was mobilized to fight him, but they were no match for the Ruler of Flame and he offered them an ultimatum, surrender to the fiends or be destroyed. When they attempted to fight, Zedonius used his fire powers to incinerate them. He then taunted Ryu Hayabusa into confronting him and the Dragon Ninja soon confronted the Ruler of Flame at a clock tower. Zedonius attacked the Dragon Ninja with murderous rage, but was defeated, consumed by fire beyond his control. Ryu told the Ruler of Flame that righteous flames would cleanse the Earth of the fiends, while the Greater Fiend screamed in pain from the fire and eventually blew up with the tower. However upon entering the Underworld, Ryu confronted a reincarnated Zedonius, who said that in that in the Underworld, his powers were absolute. The Ruler of Flame attacked the Dragon Ninja to ensure that the ritual to free Vazdah went uninterrupted, but was no match for the True Dragon Sword and died permanently, consumed by the magma rivers of the Underworld.
Zedonius is able to fly with his wings and can use fire magic. His array of attacks involve flying into the air, then slamming down onto the ground to unleash a fire shock wave, shooting fireballs, slamming his foot into the ground to shoot up a blast of fire, and charging his claws with flames to strengthen his melee attacks.
Zedonius has nothing but contempt for humans, often referring to them as "apes" or "monkeys". This most likely comes from from the days when fiends ruled over humans. Zedonius is also murderous and wrathful and displays great ferocity in battling against Ryu. He is confident that the humans will never be able to match the fiends, but Ryu proved this wrong.
- Zedonius possesses the "Malevolent Heart of Flame".
- He states that he is the one who gave humanity fire.