Chernabog is a gigantic, muscular, humanoid demon. His skin is entirely colored black, and he is so large that Sora is roughly half the size of his head. His head sports two curved horns; he has four fangs in his mouth, and his eyes are a glowing yellow. He has enormous, black, bat-like wings, and his wingspan is larger than he is tall. Chernabog is always seen trapped from the knees-down in a volcano.
Chernabog's world, Symphony of Sorcery , was destroyed prior to Sora's trip to the End of the World , and, like other destroyed Worlds, fragments of the Symphony of Sorcery appeared there. In this case, Bald Mountain, Chernabog's lair, survives, as well as the resident demon. On their way to confront Ansem, while fighting his legions of Heartless, Sora, Donald, and Goofy encounter Chernabog. He wakes up and promptly attacks the trio, but is defeated after a battle in an explosion of fire. Once defeated, a hole will appear on the mountain where he was standing, leading you deeper into the world. After Sora restores the Worlds, Chernabog returns to his home World, and isn't encountered again until Sora, accompanied by Riku, visits the Symphony of Sorcery in Kingdom Hearts 3D: Dream Drop Distance.
Chernabog appears in one of Roxas's dreams.
Chernabog appears as a Scratch Card icon on the Villains Card.
Riku battles Chernabog after he is summoned from a volcano by Young Xehanort.
Chernabog first appeared in Walt Disney's Fantasia, during the Night on Bald Mountain segment, in which he erupts from the mountain in the same way as in the game. Chernabog awakens on top of Bald Mountain on Walpurgis Night, and uses his dark powers to raise ghosts, skeletons, demons, witches, harpies, goblins, and zombies from a nearby town. He summons fire and lava, and makes the wretches in his control dance and fly around, before he destroys them.
However, the Angelus bells suddenly begin ringing, heralding sunrise, driving Chernabog and his slaves back into hiding, as a line of monks proceeds through the forest and a ruined cathedral to the sounds of the "Ave Maria".
His name is taken from the Slavic deity Crnobog, whose name means "black god". However, Disney designed him with Satan in mind. His Japanese name, "Demon of Fantasia", references his role in Fantasia, the Disney film he first appeared in.
- Chernabog is one of only eight enemies in the original Kingdom Hearts who do not have entries in Jiminy's Journal. The others are AntiSora, Bit Sniper, the Cave of Wonders Guardian, Shadow Sora, the Crank Tower, Glut, and the World of Chaos.
- By Kingdom Hearts 3D: Dream Drop Distance, Chernabog was officially credited under the Character files entry in the Reports section.