Undertale meets Shield

Blue magic

Once each group and Thor went into their separate ways, the tunnel openings suddenly began to close. Frisk looked back in fear and gripped the knife in their hands while Tony tried to scan the tunnels for traps. "Hey kid?" Tony asked, Frisk looked over to him. "You got any idea why I can't get a read on this hallway?" He asked while putting a hand on his hip and pointing his thumb at the halls. Frisk took a deep breath and looked ahead. "It might be that this place is using so much magic?" Frisk asked, Tony sighed and walked on. It began to be silent and since Tony's tech was useless, he tried making some small talk.

"Sooooo." Tony said, Frisk looked up at him as they walked. "You sure seem to care about these monsters?" Tony asked. "You seem to care a lot about your tech." They answered, they looked ahead while Tony looked at Frisk, he sighed and made his helmet disappear. Like in civil war at the airport fight. He kept looking at Frisk before shrugging off the rude comment. "Can I ask you something?" Tony asked, they didn't answer. "How did you end up here? How did you meet these monsters?" He asked, they kept quiet. "I know it wasn't because you wanted to free these guys." He said, Frisk stopped behind them and moved their gaze to the ground. He turned to them with confusion. "Kid?" He asked.

"It was because of my family." They said, Tony was confused. "But my tech says you don't have any family." Tony said, Frisk grabbed their arm. "Frisk doesn't have a family, Tina does." Frisk said, they moved their gaze to Tony who was even more confused. "My real name is Tina Foster."

With Nat and Bruce...

The two were walking in the hall silently. "If this is supposed to be a test, it's a weird one." Nat said, Banner nodded, it was quiet again and Nat shifted her gaze to him. "Hey Banner?" She asked, Banner looked at her. "Who's side are you on?" She asked. "Uh," He said and blinked. "Could you elaborate on this?" He asked, clearly confused as to what she meant by this. Nat sighed as she stopped behind Banner. "Are you trying to help the monsters or shield?" She asked as Nat folded her arms. He stopped and waited a moment before sighing. "I honestly don't know at this point." Banner said and sat against the wall. "For some period of time in my life, I've been considered a monster. Now that I'm with you guys and shield, I'm a hero." Banner said and looked over at Nat. "I can't just leave Shield and help monsters." He said.

"But you also can't leave those monsters at Fury's command. Who knows what he'll do with them!" Nat yelled, he looked away and she sighed. "I know you're trying to be smart about this with your head," She said and began to walk away from Banner who looked up at her. "But try to understand what they've gone through and try to listen with your heart." Nat said, her voice echoing through the halls. "She's right you know." Someone said, he looked around and finally saw a girl in a blue tu-tu as well as blue ballet shoes. "Who are you?" He asked as he sat up, the girl snickered lightly.

"I'm Integrity. Nice to meet you." She said as she bowed to Banner. He sighed and looked at the wall in front of him. " Sooo, how are you doing?" She asked as she walked towards him with grace. "Great, just don't know either or not which side is the best." He said, the soul hummed in thought before it got an idea. "Do you remember when you fought Sans the first time?" The soul asked while bowing, he looked up at her. "Yeah, but how do you know his name?" Banner asked, integrity sighed and folded her arms.

"Dr. Gaster talks about all the fun he'll have with his sons. Sure you've found out by now." She said, Banner shrugged his shoulders. "Anyways, I think you missed something." She said and snapped her fingers. "Using the magic that's around us, I can make one of your memories possible." Integrity said, suddenly the dark hallway became the old alley way of when they first fought Sans but everything was frozen. "Why are we here? What's the point of showing me something that I already know." He said as he stood up, she giggled and stood on her toes.

"Why don't we visit Sans?" She said and leaped to the tired skeleton as Banner chased after Integrity. She then stopped next to his blaster and looked at where the beam was being fired to. "Why again, are we here?" He asked again, she smiled. "Sans has many abilities, one of which I'm sure you didn't notice." She said and slowly made the memory play. "We call it, blue magic, you guys would probably call it..." She paused as the past Banner suddenly became blue. "Levitation." Banner was confused as he saw his past self being moved, then he saw what the blaster's beam could do. It has sent a giant hole through a small forest, cutting down almost all of them.

"He saved me?" Banner asked, Integrity nodded and looked at Sans and sighed. "Is something wrong?" Banner asked as he too looked at Sans. "Sans is usually considered the most strongest monster in the underground. But his life has been toyed with as if it was a game. Gaster believed if we helped him, he could try to reason with you humans." She said and sent the memory away. "But now he sees that most humans think monsters are nothing but war machines." She said and looked up at Banner. "I know you're still focused on who you want to trust and help, but we human souls died for a reason." Integrity said and suddenly disappeared.

Oh mi gosh. THANK YOU GUYS FOR COMMENTING! I literally was so confused who you were talking about because I've mainly been winging it. Can't wait to see you guys in the next chapter.