UnderChaos!: an Undertale AU

After The Fall:

"Ow..." Stormstar groaned. Why did I have to do that? They wondered. After what felt like forever they found the strength to sit up. Looking around they realized that they were far underground, with no hope of getting out from the way they came.
They stood up and started walking, not having any idea where they were going, but there was only one way to go.
Pain filled their body and they found it hard to move, but kept going anyway. Walking down the corridor, they found a doorway to their left and went through it. There they came across a flower, whom seemed to be crying. "Hello?" Stormstar whispered semi loudly. The flower was completely still for a moment so Stormstar decided to sit down, then the flower turned around with a semi shocked look on its face.
  "Greetings, I'm Stormstar. Who are you?" Stormstar said calmly, The flower replied, "Uhh... Howdy! I'm Flowey! Flowey the flower! You must be new here... welcome to the underground!"
Stormstar stared at him and blinked curiously. "Oh... heh heh... you must be confused. This is the realm where monsters, like myself, are locked away. Long ago, wizards trapped us down here using magic, and the only way out is by going through the barrier, which can only be broken using the six different types of human souls." Flowey explained. When Flowey said that Stormstar began to look nervous.
A moment later Flowey made Stormstars SOUL appear.
"HUH!?" Stormstar gasped. "See this? This is your SOUl! hmm... that's strange... it's... it's a rainbow soul. Heh heh... interesting... with this I could probably become myself again!"
Flowey said as his face made a creepy twisted smile.
"... GIVE IT TO ME!"
Flowey growled and tried to reach for the soul, however Stormstar grabbed their soul before he could, and absorbed it, their eyes glowing, the right one was glowing red, and the left was glowing pink.
  "HEY!! THAT'S NOT VERY NICE YOU KNOW!?" Stormstar shouted.
Flowey's face went back to normal, however he looked slightly frightened. A couples seconds later Stormstar's eyes went back to normal as they calmed down.
"Hmm... Uh... but, maybe I could help you? I'm sure there is a better way to do things..." Stormstar said calmly. "You... You wanna help me?" Flowey asked, "Why?"
"Hmm... I like helping people... it's the right thing to do, because it's nice." Replied Stormstar. "Well... if you want to help me... then..." Flowey began making that creepy smile again,
"...GIVE ME YOUR SOUL!" Flowey demanded.
Then, a goat like female monster cane running down the corridor on the opposite side of the room, and shot a fire ball at Flowey making him go under the underground's ground.
"My child... are you ok?" Toriel asked calmingly. "Uh... I'm fine..." Stormstar said reluctantly. Why is this woman calling me her child? Like... what the hell... I literally just met you! ... Is she crazy? Stormstar thought quietly as they sat there watching Toriel with a concerned look on their face.
  "My names Toriel, What is your name my child?" Toriel asked softly. "Umm... My name is Stormstar..." Stormstar replied. "Nice to meet you Stormstar. Follow me, I'll help you." Toriel said.
   Stormstar stood up and followed Toriel. Guess I don't really have a choice... I kinda need the help. I just wish she'd stop saying "my child" whenever they speak to me. Stormstar thought.
As they continued to walk Toriel began to explain some things.
"These are the ruins... there are many puzzles here that you will have to solve, but I'm sure you can do it!"
"Ok." Stormstar replied with a nonchalant expression.
The first few puzzles were completed with very little effort at all. Too Easy! Stormstar thought. After the first few puzzles, Toriel said...
"Hmm... you seem old enough to do this next one on your own, even though it is more challenging than the last ones..."
Shortly they came across a spiked bridge.
"Ok... here we are. Watch me first ok?" Toriel said. "Yeah... o-ok...Stormstar replied kinda nervously. "Don't worry my child, you can do it! Just watch."
Stormstar watched as Toriel completed the puzzle, and stood still for a few moments, focusing hard at the other side of the bridge where Toriel was now standing.
Stormstar suddenly glitched and teleported to the other side of the bridge, and was now facing Toriel.
"My child! How did you do that?" Toriel exclaimed. "I-I don't really know... I've never done anything like that before..." Stormstar replied with shock. "Hmm... ok. Moving on!"
They continued walking up and down different corridors, eventually coming across a door.
"Hmm... well... here we are. This is my house, come on in." Toriel said as she opened the door.