The creature, known as the Demon Reaper, was born in a single moment of grief caused when the Reaper Grim Jr. witnessed the brutal death of his demonic Nergaling half-sister Minimandy at the claws of the magically created doomsday weapon known as the Pumpkinator. After her death, Junior inherited Minnie's Nergaling powers, unleashing his grieving wrath on the robot, tearing it to pieces.
As his captors begged for their lives, an Angel, known as the Redeemer, took her her soul to Heaven, leaving Junior vulnerable to his own despair. Weakened by his emotions towards the loss of his sister, the demonic power bestowed onto him by Minnie took over, and forcibly fused him with what was left of the Pumpkinator to start his conquest on the whole underworld.
The Battle for Halloween Town
The first village that Demon Reaper siege was the nearby town known as Halloween Town. Fortunately, there were a number of people in the town who were capable of holding their own against the beast: Junior's own parents Mandy and the Grim Reaper as well as his uncle Jack Skellington. Although initially overwhelmed by the titanic creature backup arrived in the form of Mandy's personal aid Lord Pain who brought with him the Royal Guards of the Grim Reaper.
But even their most powerful weapon, the Beast of Destruction seemed to be outmatched by the Demon Reaper. Luckily for them, they quickly gained support by Dan Phantom a psychotic, immensely powerful Ghost, who had been released by the ghost of time Clockwork and sent to stall the beast.
With the beast stunned by Dan's attack, Clockwork and Grim entered the beast's body and retrieved Junior's soul. But Clockwork had a plan of his own and unbeknownst to Grim sent Junior's soul off to the Realm of Flesh and Blood. Sadly shortly after Junior left the beast regenerated and resumed its attacks on the village, showing off his ability of adaptation and almost killing Dan if a just arrived Nergal Junior didn't stop his attack.
Between Heaven and Hell
The power of the Demon Reaper, caught the interest of the devil, HIM who devised a plan to gain control over the Monster. In order to control the beast, he needed both Grim Junior and Minnie. Mimi his own daughter retrieved Minnie at the gates of Heaven and using the kind nature of Jeff and a de-demonized Mimi, managed to lure both Junior and the Redeemer in a trap.
Trapping the Redeemer with Jeff's webbing and infusing his daughter with the Devil Essence once again, Him showed his bargaining chip to Junior, he had Minnie. At first Him has no interest in harming the young Reaper, instead he proposed to help him become even more powerful than his parents ever were and to reunite him with Minnie forever. The only thing, Him asked in return was a pledge of undying loyalty.
After the young reaper refused this offer, Him toyed with the young boy, using the Minnie's Sins of Anger and Lust against him, which led to a duel between the two siblings. When it became clear that Junior wasn't what he hoped him to be, HIM decided to take his leave, taking Minnie with him as she should be sufficient to tame the beast.
He revealed his plans to use the Demon Reaper to conquer both Light and Darkness, Life and Death, as he would reign supreme. But before he can continue, Jeff turned on him and freed the Redeemer. The Redeemer made short-work of Him's plans and amputated the latter's left claw and reclaiming Minnie for Heaven. Him barely paid attention to the loss of his limb and ordered Mimi to interfere but Jeff stopped her, revealing him to be a full-blown traitor as this gave the Redeemer the chance to escape with Minnie, ruining Him's plan.
But before Him could punish Jeff for his treachery, Mimi stopped him before the trio of Mimi, Jeff and Junior could flee to Limbo. With Him's grasp to power thwarted, Clockwork was pleased and retrieved him from Limbo , leaving Jeff and Mimi at the mercy of Him who would arrive shortly after. At the gates of Heaven, the Redeemer decided that Minnie isn't ready for Heaven as long as she has feelings for her brother and let her go.
Clockwork brought Junior back to Halloween Town where he was quickly grabbed by the Demon Reaper, initiating a hostage situation that made it impossible for his enemies to attack. As the beast brags about how he will devastate the universe, Minnie appears on the battlefield. She tries to control the creature but he laughed at her, devouring both her and her brother.
Inside the beast, Junior locates Minnie and freed her for the tentacles of the beast with the help of Nergal Sr. Minnie managed to stun the creature from the inside, prompting Dan to take revenge and blasted the beast, levelling a large part of the town in the process. But even his most devastating attack seemed not enough to kill the Demon Reaper, who has taken form of a demonized Junior.
But before the demon can retaliate against Dan's attack once more, Minnie hugs him. The soothing feeling of this reunion gained Junior finally the power to control his powers and the Demon Reaper retreats. With the beast defeated, the Crisis is over but the whole crisis surely left a mark on the Underworld.
In the aftermath of the battle, the Grim family counted their losses, consisting of Nergal Sr. and Minnie. With the help of the citizens of Halloween Town however, they were able to give Minnie's soul a surrogate doll body but were unable to save Nergal Sr. HIM, having lost not only his claw but also a perfect opportunity to gain the most powerful weapon in the Underworld, punished both Jeff and Mimi, killing the spider and trapping his soul in a cage as extra punishment for his daughter. He gave Mimi a new task and if she really loved the Arachnid, she better not fail.
Conflicts, Battles and events
The following Conflicts, Battles and events are part of the Demon Reaper's Crisis