(Underground)

As Death the Kid rushed through the corridors as fast as his board could carry him, he was suddenly met with a little dark ball flying straight at him. It was similar to the creature Baku summoned before entering the catacombs of DWMA, but it had a little paper tag attached to it by a string, which promptly exploded when it was right up in Kid's face, knocking him down. When he got back up, he was shocked to see, further down the hallway, dozens of these explosive creatures were laying in wait, staring the boy down with their singular red eyes.

Kid: These pest, they explode when you touch them it seems...so haphazardly placed...uggggh!

He fell to his knees, physically ill just from seeing the unsymmetrical arrangement of the "Baku Bombs".

Liz: Wha-?! Kid! We don't have time for this, just shoot our way through!

Kid: I can't. It's so ugly I can't even bear interacting...I'm such a piece of garbage that a bunch of eyes became the world's downfall...

Liz: Y-You, you can't be serious... The Kishin is about to be resurrected, but THIS is what stops you?!

Kid: I guess so...

Liz: Sigh...Patty, get him moving.

Patty: Sure thing!

...

Patty: GET A MOVE ON, YOU USELESS PIECE OF SHIT!!!

Kid: Geah!!

Frightened by his gun, Kid rushed through the bombs, shooting them out of the air left and right.

Liz: Had a feeling that would work. Nice job.

Patty: Hee-Hee, thanks sis!

Up ahead, Baku and Eternal could hear the explosions going off.

Eternal: Whoa! Guess one of 'em got past Crona!

Baku: It's the Shinigami's son, he's headed this way. Hm, we're closing in on the chamber but he'll catch up before we make it in time... One moment.

He placed his hand on Eternal's shoulder, and two copies of the duo appeared from their bodies like mitosis, jumping off the flying creature.

Baku: Hopefully those two can hold him off long enough, I had to halve both our souls...

(The copies are now are attention.)

Eternal: Huh, I didn't know you could clone other people, neat!

Baku: We are only half as strong now, so fight seriously when he gets here. We only have one shot at this!

Eternal: Roger-doger!!

Baku: ...You're going to be the death of me one day.

The clones saw the Shinigami boy approaching, and Baku set up a blockade of twisting branches.

Baku: You're not going past us, boy! The Kishin will soon be revived, and you'll be too late to stop it!

Kid: I don't have time for this, out of my way!

The Shinigami attempted to rush and shoot his way through, but the cyclops' right arm molded into a massive blade and swung at his chest, knocking him back.

Kid: So he's a Demon Weapon?? Then that means, his Meister is...

Baku: Now you'll experience the sharpest of swords that is me: Baku, the Dark Matter Blade!

And with a flash of purple light, Baku transformed into a black sword, nearly as tall as Eternal, standing at a solid 7 feet.

Eternal then took the blade, and he began generating an enormous amount of energy from his soul.

(I forgot to show the drawing of Eternal's soul during the bridge fight.)

(And for Baku, it doesn't have any defining features I could think of.)

Kid was shocked by the massive increase in power, but even more at the asymmetrical horns and the X. But he had to put it aside for this situation. The Demon's left eye, or lack there of, closed, and then opened to reveal a red eye. Along with that, his expression changed from the usual goofy smile, to a more mature, battle-ready appearance.

Kid: His soul feels different now, as if both of them merged....

Eternal: Now, feel my sword's might!!

The Demon swung his Dark Matter Blade with incredible speed, reaching Kid in a split second. The Shinigami's son avoided this slice
by performing a backflip and landed behind a ruined pillar.

Kid: He's faster than I expected, too! And if it's true that this creature is immortal, I need to incapacitate him somehow.

Distracted in his thoughts, Eternal had already made it to the pillar where the Meister was hiding behind, and cut straight into Kid's right arm, knocking him into the wall. The blade cut directly to the bone, and the wound burned horribly.

Getting back on his feet, Kid fired several shots at the Demon, who let each one hit. And after he was filled with holes, they each closed just as fast as they appeared.

Eternal: Useless, useless! This body cannot be killed!

The dark blade ignited with a purple flame as Eternal rushed in for another attack. With each swing of the powerful sword, the Shinigami just barely missed the flames by mere inches, and he shot the demonic swordsman every chance he got, but to no avail.

Eternal: You can shoot me all you want, this vessel will just keep regenerating! You, on the other hand...

Kid: This is the real deal, just like with the necromancer before. I have no choice then.

Eternal: You want to fight seriously now? Alright then!

Kid then fired the energy ball at Eternal dead-on, causing a massive explosion.

Kid: There, he should be vaporized by tha- What?!

To his shock, the Demon had indeed taken damage, all the way down to the skeleton. But within seconds, new muscle, organs and skin grew back, even his white pants returned.

Eternal: ...Is that all?

Kid: N-No way! Not even the Death Cannon works?? Now what, I can't beat these guys without he-

Black★Star: YA-HAH!

The assassin Tech ran right over Kid, clashing blades with Eternal.

Eternal: Ah, it's you again, Star Clan boy! Now I can get you back for our previous fight!

Black★Star: Just try it, you ain't resurrecting the Kishin tonight!!

Kid: Ugh...Black★Star?! Whatever, just help me take these guys out!

As the Shinigami covered Black★Star from a distance, the assassin rapidly slashed at Eternal's body.

Black★Star: Big Wave!!

The boy sent a punch to Eternal's jaw, sending his Soul Wavelength throughout his body. For the first time since this fight began, Eternal had now shown visible pain.

Kid: That's it! Black★Star, keep hitting him with your Soul Wavelength, it seems to be the only thing that hurts him!

Black★Star: You got it!

He punched the Demon several more times in perfect succession, causing Eternal's soul to waver.

Eternal: Shit! He's weakening my connection, I can't handle another one of those!

The Immortal Demon attempted to swing his sword, but Kid quickly shot both of his wrists, forcing him to drop the blade. Now defenseless, Black★Star raised his sword, and slashed wildly, cutting Eternal into pieces. With one final punch, Black★Star shattered the Demon's body, causing it to disappear in a puff of smoke.

Black★Star: Hell yeah!!! I got him! The mighty Black★Star has just saved the whole world, haha!!!

Kid: You idiot! It was just a distraction!

Baku: C-Correct...

Baku, now in his humanoid form, was now fading in and out of vision, like a broken hologram.

Baku: You may have defeated my two copies, but the real ones have just made it to the Kishin's chamber, and are about to enter it to revive the Demon God!

Kid: What?!

Baku: You're too late to stop them now, prepare to face true Hell, hehe!!

And with that, the clone disappeared.

(Back to the originals.)

Baku: Hm? Our copies were defeated just now, the assassin kid got them. No matter, we finally made it.

The two Demons stepped through the large doors, and now made there way through the dark chamber of pillars.

Baku: This place seems to go on forever, do you see the seal anywhere, Eternal? ...Eternal?

Baku turned to see why his Meister was so silent, but was only met with a figure wearing bandages over their face.

Baku: Wh-What the?! Who're you? Where's Eternal?!

???:...

Baku: Answer me, you little-urk!

The long, hand-like scarves around the man's neck wrapped around Baku's, and the Demon felt a horrible, unnerving fear in the presence of this person, this creature. The man walked closer to Baku, showing his disgusting teeth.

Baku: No...k-keep away! U-UAHHH!!!!

Eternal: Eh?

While he took the lead, Baku suddenly fell to his knees and began muttering something to himself.

Baku: No, my face, my face...!

Eternal: What's up with you, what about your face?

He went to go check, and suddenly Baku looked up, now with three eyes, and the horrid smile. Before Eternal could react, Baku sent his hand straight through the Immortal's chest.

Eternal: Whoa, buddy! What's up with ya? You're starting to creep ME of all people out!

Then, without hesitation, Baku went up and animalisticaly bit his face off.

Eternal: Holy shit! What's this feeling in my gut? Is this...is this fear? I can't die, but...I'm scared??

But before he could get that question answered, the two Demons found themselves in unusual positions. Baku had a small dagger inches to his throat, and Eternal had nearly cleaved his own head off with a large blade.

Eternal: Huh? Was that a dream or something? Where'd I get this blade?

Baku: Thank God! It's just an illusion. To think, the Kishin is sealed away, and even then his power can effect us!

Eternal: Let's hope Fennyboy knows what the hell he's doing here!

Baku: Since it only messed with our heads here, then it must mean...

At the very end of the room, they could see just what they were after, the first Kishin, the first Demon God.