Two years had passed since the Digimon Tamers had defeated the rogue program, the D-Reaper, as well as Parasimon and his horde of parasitic brethren, bringing peace and order to both the Real World and the digital World.
However, that peace wasn't to last forever, for a new evil was coming, and was closer to the Tamers than they expected.
Currently, in Shinjuku's park, a great darkness was building up inside of Guilmon's old shed, which had caught the attention of the dragon Digimon and caused him and Takato to investigate it.
As the pair continued making their way to Guilmon's old home, he placed his hand on his stomach.
"Takatomon, my stomach doesn't feel good." He said.
"Do you think it would have anything to do with the big breakfast you had, not to mention mine?" Takato asked, thinking Guilmon just had a stomachache from overeating.
However, Guilmon shook his head.
"No. My stomach doesn't hurt from food." Guilmon replied, before saying. "It feels… wrong. I feel something building in my shed. And the closer I get, the more it hurts.
Pushing forward, Takato and Guilmon eventually arrived to the entrance of the shed, to which both could see a powerful darkness was emitting from within.
"W...what is this energy?" Takato asked, feeling it's dark presence, it felt somewhat familiar, like he had encountered it before.
However, the darkness suddenly grew, pushing Takato and Guilmon back, before both sat up and watched as a Digimon emerged from the the dark void.
Growing in size, the Digimon let out a fearsome roar as it burst right through the roof, destroying the shed, before it glared down at Takato and Guilmon.
They were surprised at the sudden appearance of the dark Digimon, especially Takato, for it looked quite familiar to him.
Quickly removing his D-power from his Jacket, Takato held it toward the Digimon and was shocked at the reading.
"BlackWarGreymon, a Dark Virus Digimon, Mega Level." He read aloud.
The main reason Takato was shocked at seeing BlackGreymon was because of the Digimon Adventure series.
He remembered how powerful and dangerous the BlackWarGreymon was on the series and was worried about the safety of Guilmon, the residents of Shinjuku and wondered if he could even defeat such a Digimon.
Snapping from his doubt, Takato told his Digimon partner in warning. "Guilmon, we have to be careful with him. He's one of the strongest Mega Level Digimon I know."
Guilmon nodded in reply as he got back up and stood before Takato, ready to fight.
But before either side made a move, a familiar female voice called out. "Takato!"
Turning around, Takato and Guilmon saw Henry, Terriermon, who was sitting on his Tamer's shoulder and Rika run up to them, while Renamon, using her great speed, appeared beside Guilmon.
Seeing his friends, Takato had to ask. "Rika? Henry? What are you guys doing here?"
"We came to help." Terriermon answered for them, before rushing over and joining Guilmon and Renamon.
"Did you really think we'd miss out on a chance to fight?" Rika asked, making Takato smile at her.
"Not at all, but we have to be careful. BlackWargreymon will be one tough Digimon to defeat." Takato told his friends, as he withdrew a Blue Card.
"Right!" Henry and Rika replied as they too drew a Blue Card each, before the three swiped each Card through their D-Powers.
"Digi-Modify! Matrix Digivolution Activate!"
"Guilmon Matrix Digivolve to... WarGrowlmon!"
"Terriermon Matrix Digivolve to... Rapidmon!
"Renamon Matrix Digivolve to... Taomon!"
After the three had Digivolved to their Ultimate forms, determination filled their eyes, while BlackWarGreymon just stared at them, showing no worry that he was outnumbered and up against an incredible force.
"You really think you can beat me?" BlackWarGreymon then asked in a dark and arrogant tone, before saying. "Don't make me laugh."
"How about I make you cry instead? Rapid Fire!" Rapidmon yelled back, before he unleashed several missiles from his arm cannons, consuming BlackWarGreymon in a powerful blast.
They waited smoke to clear, before they were shocked to see BlackWarGreymon standing in the same spot, and didn't even have a single scratch on him.
"If that's all you have, defeating you will be far easier than I thought." BlackWarGreymon commented.
"Terra Destroyer!" He then yelled, gathering a great amount of negative energy that he then threw at them, which Rapidmon and Taomon managed to avoid, while WarGrowlmon was struck by the attack, creating a powerful shockwave as the blast collided with him.
"WarGrowlmon!" Takato called out in concern, watching as his Digimon partner then collapsed from the strain the attack put on his body, followed by Takato, as he felt the pain WarGrowlmon experienced.
Seeing Takato fall too concerned Henry and Rika, which increased as the brunette grasped his chest, while crying out, making Henry and Rika look in shock to see BlackWarGreymon had switched from long range to close range and was slashing his claws across WarGrowlmon's chest and face.
"You are pathetic." BlackWarGreymon said as he continued to attack WarGrowlmon. "It's like you're not even trying to fight."
Bringing his right arm forwards, about to slash at WarGrowlmon again, BlackWarGreymon was caught off guard when Wargrowlmon suddenly grabbed his fist into his own.
"That's because I'm not. I'm doing what I have to in order to protect Takato and my friends." WarGrowlmon told BlackWarGreymon as he then grabbed his left fist.
"And I'll never give up!" WarGrowlmon then yelled, before spinning BlackWarGreymon around and throwing him into the air, allowing him, Rapidmon and Taomon a clear shot.
"Atomic Blaster!"
"Rapid Fire!"
"Talisman of Light!"
BlackWarGreymon was defenceless as the three attacks hit him, consuming him in another blast, before he plummeted to the ground.
Slowly rising to his feet, he was approached by WarGrowlmon, while Rapidmon and Taomon landed on his sides.
"Alright, BlackWarGreymon, give up and go back from where you came!" WarGrowlmon said.
However, his demand made BlackWarGreymon chuckle, which then turned into wicked laughter.
Confused, Rika demanded. "What's so funny? Mind filling us in on the joke?"
"The joke is you. You all believed you had won, but I haven't even shown you my true power." BlackWarGreymon replied, which shocked the Tamers and made Takato ask. "Wait, you've been holding back this entire time?"
"That's right." BlackWarGreymon said as a dark aura encircled him.
"And now to show you what true power is! Black Tornado!" He then exclaimed and started to spin around at a rapid pace, before lunging through the area and striking WarGrowlmon, Rapidmon and Taomon, knocking the three down.
Unable to maintain their forms, WarGrowlmon, Rapidmon and Taomon De-Digivolved to their Rookie form, while Takato, Henry and Rika fell too, bearing the tremendous pain their Digimon partner felt.
Still in pain, but refusing to give up, Takato and Guilmon started to get to their feet, determined not to lose.
"W... we can't let him beat us... we need to fight Mega against Mega!" Takato called out as he withdrew his D-Power again and exclaimed. "Biomerge Activate!"
Using his D-Power as the conduit, Takato and Guilmon combined their energy and beings into one, who then called out. "Guilmon Biomerge to... Gallantmon!"
Seeing Takato and Guilmon continuing to fight and not give up, gave Henry, Terriermon, Rika and Renamon the strength they needed to get back up and assist their friend in his fight.
"Biomerge Activate!" Henry and Rika called out, as they too pulled out their D-Powers for a second time and fused with their Digimon partners.
"Terriermon Biomerge to... MegaGargomon!"
"Renamon Biomerge to... Sakuyamon!"
Seeing the Tamers Bio-Merge made BlackWargreymon ask, his tone remaining as arrogant as ever. "You think you can beat me in those forms?"
"We don't think it, we know it!" Gallantmon said back.
Gallantmon's statement just amused BlackWargreymon, that was until he a blast of energy shot past Gallantmon and struck the Black Digimon in the chest, making him stumble back.
Looking from where the blast had been fired, BlackWarGreymon, Gallantmon, MegaGargomon and Sakuyamon watched as Beelzemon, holding up one of his shotguns, which had smoke emitting from the barrel, then stepped out of the lush wilderness and into the clearing.
"This a private party or can anybody join?" Beelzemon asked, as he withdrew his second gun, aiming them at BlackWarGreymon.
"Sure Beelzemon. And in time too, we were just getting our second wind." MegaGargomon replied.
Annoyed and angered by Beelzemon's attack, BlackWarGreymon roared out. "This changes nothing! It doesn't matter if I'm up against four or four hundred, I will destroy you all!"
"Terra Destroyer!" BlackWarGreymon then exclaimed, unleashing all his rage into a single attack directly at Gallantmon and Beelzemon.
"Lightning Joust!"
"Double Impact!"
Gallantmon and Beelzemon unleashed their own attacks, doing their best to hold BlackWarGreymon's back.
"You cannot win! I will eliminate you both!" The Dark Digimon yelled.
"Hey!" MegaGargomon called, breaking BlackWarGreymon's concentration to see the Machine Digimon leap over him, alongside Sakuyamon, before landing beside Gallantmon and Beelzemon.
"When you mess with one of us, you mess with all of us!" He then stated, as the gun turrets on his shoulders opened up, while the tip of Sakuyamon's Kongou Shakujou spear was consumed in light blue flame.
"Gargo Missile!"
"Fox Drive!"
With the added power of MegaGargomon's missiles and Sakuyamon's spiritual flames, BlackWarGreymon was in shock to see his attack being pushed back.
"Impossible! How are you able to stop my power!?" He questioned.
"Your power comes from hate, while ours' comes from trust." Gallantmon told BlackWarGreymon, before he stopped his attack, knowing he could count on his friends as he prepared to finish the Dark Digimon off.
"Spiral Saver!" Gallantmon then exclaimed, charging through the combined attack of his friends and right through BlackWarGreymon's, who could only watch in shock before Gallantmon's lance shot through him, defeating the Black Digimon and causing him to drop to his knees.
BlackWarGreymon looked at them as his body began to fade and started to turn into nothing but Data particles.
"You think you have won? It's not over, not by a longshot... there are more there five more Digimon who serve the master of the Hazard." BlackWarGreymon said, ignoring the pain he felt, while his armour digitized into nothingness, revealing a familiar Hazard symbol on his forehead, just like the one Guilmon had on his stomach.
Hearing BlackWarGreymon's statement, Gallantmon questioned. "Who are they, and who is this Hazard master?"
BlackWargreymon just smirked at Gallantmon's statement and his confusion.
"You'll find out soon, Guilmon..."
With his final words, what remained of BlackWarGreymon was reduced to mere Data particles, causing Gallantmon, MegaGargomon and Sakuyamon to revert back to their original forms, and left them with many questions.
Turning to Guilmon, Beelzemon asked. "You know that guy?"
"Guilmon never seen him before, but he gave me a bad feeling in my stomach." Guilmon said in reply, placing his hand back on the Digital Hazard mark, making Takato say. "Ok, it's definitely not a stomach ache."
While trying to figure where to go to or what their next move should be, a shadowed figure, hiding amongst the trees, smirked as they stared at Beelzemon.
'Not bad. Maybe I can convince the Hazard master to spare you if you offer your services to us.' They thought, smiling slyly, before vanishing, leaving the Digimon Tamers none the wiser.