Demongo is the main antagonist of the episode "Demongo the Soul Collector" of the Gotham Crisis series, prequel to When Phineas meet Nobita series.
The Black Mass, an evil entity attacked the universe. Odin, Ra and Vishnu arrived to pursue the mass. After a fierce battle, the three Gods finally defeated the Black Mass. However, one fragment survives and drifts away into the cosmos to find a planet to dominate.
The fragment finds earth and lands in. As life on Earth begins to evolve, many people and animals get destroyed by the thing. However, the humans and Birdpia people attempt to destroy the Black Mass by burning it, which only revolved in the Black Mass becomming a pyrotic demon by the name of Demongo.
After this, Demongo thanks the warriors for releasing him. He took their essence and get more powers. Then, Demongo teleports himself into the future, where there's more people to take essence. However, Odin, Ra and Vishnu knew this, locked the time. While people can travel through it, Demongo can't. However, the gods didn't locked one, the time of 5000 years later. Demongo opens it with the help of someone from the future. As a side effect of time, Demongo has to became a henchman of anyone who release him.
Demongo was released by Darth Sidious and was ordered to find, kill, and steal the soul of ObiWan Kenobi, his master's enemy. Demongo happily took his new assignment and pursued him immediately.
Demongo catches up with ObiWan in a remote canyon far away from any civilization. Demongo introduces himself and informs ObiWan of his intentions right away. Demongo starts the battle by summoning a warrior by the name of Titan who is fairly big. ObiWan tricks Titan into hitting the side of the canyon cause a huge bolder to fall and kill him. Titan dies and his soul is absorbed by his master. After Titan's presumed demise, Demongo summons 5 more warriors who are not named, but are all eventually defeated. Upon seeing this, Demongo summons them once again. ObiWan asks how this can be and Demongo tells Jack that souls can be defeated but not killed. Demongo, after seeing his minions defeated once again, summons every soul he has collected over the years. ObiWan, after a long struggle, defeats the remains of Demongo's minions. As the last soul is sucked back into Demongo's chest, ObiWan grabs it and its brought into Demongo's realm. ObiWan, once inside, frees the souls of all of the warriors in Demongo possession. As a side effect Demongo loses all of his powers, rendering him powerless. As if nothing can get any worse for him, all of the warriors he has kept in enslavement are free to take their revenge. Demonogo is "killed" and is trapped within a skull-like prison. He then finds himself in Palpatine's hands and begs for another chance. Sidious thinks it over for a moment, but decides against it and kills him.