Undertale meets Shield

The human souls

The next morning, Frisk began to lead the group through snowdin. They told them to watch out for any types of traps that would still be around the place. Thor and Tony simply flew over them, Nat used her abilities to jump through the trees while Clint, Steve and Bruce followed Frisk. "Why are there so many?" Clint asked Frisk, referring to the traps. They had to stop because Bruce got stuck in a quicksand trap, in the snow. "The monsters would do anything to break the barrier faster." Frisk said and sighed nervously. "Even though they kinda forgot that we humans can be just as fragile as the monsters." Frisk said, Clint looked at the trap to see Thor struggling to pull out Bruce. He then looked to his left and saw a child staring at him. He shook his head and looked at the spot again to see no one. They kept on walking or flying until they reached Alphys lab.

"This place looks old." Tony said and held up his repulser. It made a noise before shooting a beam and melting the door. Frisk then stepped in front of the avengers. "Before breaking the barrier. I met Gaster and he tried getting my soul." Frisk said, Nat seemed confused. "Didn't all the monsters in the underground do that so they could go free?" Banner asked, Frisk sighed as four buttons appeared in front of them. Act, Item, mercy and FIGHT. "Yes, but Gaster tried to get it so he could get out of the void. Determination is a unique soul trait, only two humans had it." Frisk explained and hovered their hand over the ITEM option.

"Perhaps this monster had taken the other determined soul?" Thor asked as Frisk pushed the button and reached their hand in a pouch. "No. Their soul is too damaged to be used." Frisk said, they took a deep breath and pulled out a knife. The avengers looked at Frisk who stared at the knife. "Ever since you fought them, I haven't seen Chara." They said and looked at the avengers, some of them looked guilty while Tony didn't. Once they had suited up, they walked into the quiet, dark and cold lab.

Tony was walking next to Frisk who seemed to have lots of guilt. He looked at them, in an attempt of trying to figure out what they were thinking about. Tony was about to open his mouth to say something. "We got a problem." Nat said, Frisk looked up to see the hallway split into four corridors. "Which way do we go Frisk?" Nat asked as Frisk walked to the front. Four black sludges then appeared in each hall. Frisk yelped and stepped back. The sludges took four different shapes. One was a boy with a white apron and a frying pan in hand. Another with a girl with a bow in her hair and a knife in her hand. Another was a boy with glasses and a book and the last one was a girl with a piece of fabric tied around their head and boxing gloves on.

"The human souls..." Frisk whispered to themselves, the souls opened their pearl white eyes. "Welcome Avengers and Frisk, the human soul of determination." Patience said with a smile. "Who are you four?!" Clint yelled, clearly creeped out. Tony aimed his repluser at them. Kindness raised his frying pan and a shield appeared around it, not cutting through his arm. "We can't have you do that." Kindness said, Perseverance stepped forward. "We know why you're here." He said with a frown. "But how are you here?! I thought your souls disappeared when the barrier broke!" Frisk exclaimed, Bravery sighed. "Yeah, but our magic went to the void, the science guy saw it and used it to bring us back." Bravery said in a new jersey accent. "He needs our help to come back to the real world." Bravery explained.

"But even with all of our magic combined, Gaster couldn't fully come out." Kindness said and stepped closer. "You're saying you helped him?" Banner asked, they nodded. "We want to help you but you have a traitor amongst you." Patience explained and held up her knife to the Avengers and Frisk. The avengers went wide eyed as the souls began to hover. "In order to find out who it is, you all will split into groups of two." Kindness explained, but then he counted and saw there were seven. "Uh, someone will go alone." Kindness said, Perseverance smacked their forehead as Bravery chuckled and Patience gave a nervous smile. "I shall go alone!" Thor declared, the souls smiled while Nat smacked her forehead.

"Very well, Nat shall go with Banner." Perseverance said and opened their book. "Frisk with Tony and Clint with Steve." They said, the group nodded as their souls then faded away. The group then began to split up. "Be careful Frisk, I don't trust him." Chara's voice said in Frisk's ear. "Chara?" Frisk asked as they whipped their head behind them only to see the empty hall. Frisk sighed and looked at the knife in their hands. "Frisk!" Tony yelled, they jumped slightly and turned to see light emitting from Tony's suit. "Come on kid, the faster we go through these halls, the faster we can fix everything." Tony said, Frisk nodded and ran after him. Once he turned his back, another sludge appeared. It then took the shape of a person and became Chara. "Stay determined." They whispered before turning to ooze and disappearing once again.