The Fallen Story [Undertale AU]

Ch3 : My sunshine.

Sans teleported to the extraction lab along with Mynx.

"Alright get any DNA samples you can."

Mynx nodded, "On it."

She scanned the area looking for anything, Sans stayed close behind making sure there was no one else there.

"I got something!"

Sans gave her a DNA sample jar and she put it in it.

"We gotta give this to alphys and then..-"

Suddenly something shot at them, barely missing Mynx.

"What the hell are you doing here."

Chara shouted at them angrily. Before she could make another move Sans grabbed Mynx's arm and teleported to Alphys' lab. Her regular lab.

"ALPHYS!"

She looked at them, "Y-Yeah..?"

"We need a DNA test pronto!!"

They handed her the vile of the liquid and she analyzed it.

She then gasped, clutching her chest and breathing heavily.

"O-Oh my god.. Oh my god oh my god.."

"Alphys what is it?!" Sans looked at her nervously.

"S-Sans.. T-They're Seishin.. T-They're both Seishin..!"

Sans looked at her, "No.. No No NO.."

Mynx looked at Sans.

"Sans whats a Seishin..?!"

"A monster soul.. But it.. It.. Its not a monster like me.. Its a monster as you heard as a child.. A beast.. It combines the soul with negativity.. Making it the opposite of what it was.. Corrupting their soul. Then their soul is live-like. Dripping with eyes like we saw. They kill people for power, or infect them. If they cant kill them.. They will stab them.. Infecting their soul.. And when theres enough those who are infected.. Become true monsters.. Humans loose Human abilities.. They become beasts.. And monsters.. They grow these weird.. Things.. Sometimes loosing limbs.. Growing arms.. Double heads.. Mynx they become mutated.. And if that thing got you.. Your infected.."

Mynx starred at him horrified. "How do I undo it..?!"

Sans looked at Alphys. "Please tell me theres a way."

She shook her head sadly. "N-No.. Just hope.. She d-doesnt get anyone else.."

Mynx looked at Sans. "Am I going to die.."

Sans looked down, unassure what to say. "No.. I will kill that thing. And you will be fine.. Can I see your soul..?"

She nodded holding out her soul. It still remained as "animalism" One who can become certain animals they hold a special relation with.. But it was corrupted. Her soul color was very, very dark. The colors were dimmed, almost grey.

"Its infected.." Sans replied.

Mynx hugged him tightly. "Were going to fix this. I promise."

He sighed and hugged her. "I hope your right."

Alphys replied nervously. "Y-Your going to need some help defeating them.."

Sans looked at her, "Who will help us..?"

Mynx then looked at him, "How bout Flowey?"

Sans almost looked disgusted. "That fuckin' weed?!"

Mynx groaned, "He may help us if he understands the trouble this world is in."

Sans sighed. "Fine we can try, lets go."