A fight for power

After what seemed like an eternity in the dark universe, Corrupted!Toriel made the decision to meet with Correct!Sans out of boredom, but not before falling asleep in a former recollection of how she killed her creator, the so-called goddess of all, as she claims. She recalls how they thought in a void in-between the mutiverse.

Corrupted: Well well well, look who we have here. If it isn't the so-called creator who abandoned me!

Yggdrasil: Corrupted I thought I imprisoned you in the dark universe for good. How annoying.

said Yggdrasil as he finished speaking. Corrupted charged at full speed, as if she had just teleported, but Yggdrasil easily stopped her attack with nothing more than her finger. With a wave of her hand, she sent her flying into the ground before hitting the ground hard, causing her to shake her head in distress.

Yggdrasil: You're wide open!

As he slammed her leg on to the ground, she caused the entire void to shake from the force. As Corrupted looked at the huge crater in the ground, she seemed a bit scared, but at the same time extremely excited for what was about to happen. Without a second thought, tried to attack her from behind, only to get thrown into the air and fly higher and higher.

Corrupted: What the hell is this? This is bullshit! There is no way I'm weaker than this old hag!

As Corrupted spoke, a hand rested on her shoulder.

Yggdrasil: Umm, who are you calling an "OLD HAG!"?

As Corrupted summoned her scythe, she swung it at light speed, instantly cutting the large void in half. Looking in front of herself, she couldn't seem to find Yggdrasil, who appeared behind her.

Yggdrasil: Impressive. You're actually kind of strong. However, you are nowhere near to beating me dear.

Without a chance to react, Yggdrasil was off Corrupted right arm before slicing her left leg and finally half her face.

Corrupted: ARGHHHHH

She screamed in pain from the damage she took and the limbs she lost, but not too long after, her body started to regenerate from the damage.

Corrupted: Why you bitch

Screamed Corrupted as she swung her scythe at Yggdrasil, only to continuously miss each strike and end up creating shock waves around the void they were in.

Yggdrasil: you're too slow and too weak. Fighting me is fruitless. Why don’t you just give up now and save me the trouble of this fight?

Without waiting for a response, Yggdrasil punched Corrupted's so hard that she ended up breaking the edge of the void they were in and falling into the abyss of nothingness. As Corrupted continued to fall, she eventually fell too close to something called the living black hole. As the black hole swallowed her whole, she began to release a strange and powerful surge of energy that ended up shrinking the black hole until it was so small it could be held in her hand, As she opened her mouth, she swallowed the black hole into herself, which ended up sprouting wings. She flew at light speed towards Yggdrasil while destroying multiple universes and even multiverses that got in her way.

Corrupted: YGGDRASIL!

She screamed as she punched Yggdrasil with so much force that the void they were inside exploded with thousands of shards going everywhere.

Yggdrasil: WHA-what the hell?

Without a second to waste, Corrupted proceeds to pummel Yggdrasil, sending her flying into several multiverses, destroying them upon contact. Exhausted Corrupted began to feel exhausted from the amount of power she released.

Corrupted: Damn I know I have infinite energy, but damn that was a rush. I've never really tried something that intense or reckless before.

Corrupted was finishing her thought when she heard a voice behind her.

Yggdrasil: Nice try, little ant, but unfortunately for you, this is when your little show ends.

Yggdrasil, larger than the universes, smiled as she appeared behind Corrupted. She swung her arm, slamming Corrupted higher into space before appearing on top of her and slamming her foot down, crushing her between her heel and the thousands of universes underneath her. Flouting in the abyss of the destroyed cosmos, Corrupted's body began to regenerate from the attack, Yggdrasil looked on.

Yggdrasil: Wow, is this really the limit of your power or are you still holding back?

Yggdrasil telepathically speaks to her before grabbing her and crushing them to death. Corrupted felt her body being crushed by the second, only able to be awake for a few minutes before seemingly passing out, A voice started to talk in her head,

???: what are you doing? Why are you letting her win?

So said the voice.

Corrupted: Because I know I can't beat her, I'm too weak.

Replied Corrupted

???: Well if that's the case, then let me out so I can take care of her for you.

Corrupted: What??? Why should I

???: Because if you don't, you will die, Do you want that?

Corrupted: No, fine, you can have control. Just make sure you kill this bitch, okay?

???: Sure thing.

As Yggdrasil looked on victoriously, a strong pulse of purple light emitted from Corrupted's body. This forced her to let go of them before witnessing something odd. She saw Corrupted body changing and becoming larger, so large, in fact, that it appeared to be just as big as Yggdrasil herself. As Corrupted's body finished growing, she opened her eyes, roaring at the top of her voice, very shaking the multiverse and shattering multiple number of universes in the process.

Millennium: Ok now then, let's try that again.

As she spoke, her mere words were enough to shake the multiverse itself,

Yggdrasil: What is this form, what is this power?

As Yggdrasil took a minute to process what was happening, she looked up to see multiple rifts in space and time beginning to open as Millennium prepared to fire her attack. In response, Yggdrasil began to fire her attack.

Millennium: INFINITY CANNON!

Yggdrasil: GAIA STORM!

They screamed as Millennium and Yggdrasil both launched their attacks. Destroying not only the multiverse they were in, but also all of existence itself. As everything settled down, the only being left was Millennium, who reverted back into Corrupted!Toriel, as they saw the floating pieces of Yggdrasil, smiled victorious.

Corrupted: HAHAHAHA I Finally Won!

Yggdrasil: I wouldn't be so sure if I were you since you only beat 1 of my infinite number of avatars HAHAHA.

As the avatar of Yggdrasil started to fall to pieces, Corrupted was left with that single thought in her head.